diff --git a/.github/skills/architecture/hook-architecture.md b/.github/skills/architecture/hook-architecture.md
index a06951f..ce87d06 100644
--- a/.github/skills/architecture/hook-architecture.md
+++ b/.github/skills/architecture/hook-architecture.md
@@ -45,8 +45,8 @@
 
 ### Header Hooks
 
-| Hook                                    | Parameters                    | Purpose                                                  |
-| --------------------------------------- | ----------------------------- | -------------------------------------------------------- |
+| Hook                                               | Parameters                    | Purpose                                                  |
+| -------------------------------------------------- | ----------------------------- | -------------------------------------------------------- |
 | `fe_csv_import_export_basic_post_fields`           | `$fields, $scope`             | Customize basic export fields (ID, title, content, etc.) |
 | `fe_csv_import_export_additional_post_fields`      | `$fields, $scope`             | Customize 'all' scope additional fields                  |
 | `fe_csv_import_export_filter_taxonomy_objects`     | `$taxonomy_objects, $args`    | Filter taxonomy objects before header creation           |
@@ -54,34 +54,35 @@
 
 ### Query Hooks
 
-| Hook                          | Parameters           | Purpose                                        |
-| ----------------------------- | -------------------- | ---------------------------------------------- |
+| Hook                                     | Parameters           | Purpose                                        |
+| ---------------------------------------- | -------------------- | ---------------------------------------------- |
 | `fe_csv_import_export_sample_query_args` | `$query_args, $args` | Customize sample post query for meta discovery |
 | `fe_csv_import_export_export_query_args` | `$query_args, $args` | Customize main export query                    |
 
 ### Import Hooks
 
-| Hook                         | Parameters                | Purpose                                |
-| ---------------------------- | ------------------------- | -------------------------------------- |
-| `fe_csv_import_export_pre_ajax_import`  | `$result, $_POST`         | Preflight import request validation    |
-| `fe_csv_import_export_user_can_import`  | `$allowed`                | Override import capability checks      |
-| `fe_csv_import_export_before_import`    | `$args`                   | Pre-import preparation                 |
-| `fe_csv_import_export_import_row`       | `$row_data, $args`        | Per-row data transformation            |
-| `fe_csv_import_export_after_import`     | `$stats, $args`           | Post-import cleanup                    |
-| `fe_csv_import_export_cancelled_import` | `$cancelled, $session_id` | Override import cancellation detection |
+| Hook                                         | Parameters                              | Purpose                                            |
+| -------------------------------------------- | --------------------------------------- | -------------------------------------------------- |
+| `fe_csv_import_export_pre_ajax_import`       | `$result, $_POST`                       | Preflight import request validation                |
+| `fe_csv_import_export_user_can_import`       | `$allowed`                              | Override import capability checks                  |
+| `fe_csv_import_export_before_import`         | `$args`                                 | Pre-import preparation                             |
+| `fe_csv_import_export_import_row`            | `$row_data, $args`                      | Per-row data transformation                        |
+| `fe_csv_import_export_after_import`          | `$stats, $args`                         | Post-import cleanup                                |
+| `fe_csv_import_export_cancelled_import`      | `$cancelled, $session_id`               | Override import cancellation detection             |
+| `fe_csv_import_export_import_max_batch_size` | `$max_batch_size, $total_rows, $config` | Customize maximum import batch size (default: 500) |
 
 ### Export Hooks
 
-| Hook                         | Parameters                | Purpose                                |
-| ---------------------------- | ------------------------- | -------------------------------------- |
+| Hook                                    | Parameters                | Purpose                                |
+| --------------------------------------- | ------------------------- | -------------------------------------- |
 | `fe_csv_import_export_pre_ajax_export`  | `$result, $_POST`         | Preflight export request validation    |
 | `fe_csv_import_export_user_can_export`  | `$allowed`                | Override export capability checks      |
 | `fe_csv_import_export_cancelled_export` | `$cancelled, $session_id` | Override export cancellation detection |
 
 ### Import Processing Hooks
 
-| Hook                                 | Parameters                          | Purpose                            |
-| ------------------------------------ | ----------------------------------- | ---------------------------------- |
+| Hook                                            | Parameters                          | Purpose                            |
+| ----------------------------------------------- | ----------------------------------- | ---------------------------------- |
 | `fe_csv_import_export_import_row_context`       | `$context, $row_data, $args`        | Customize row context creation     |
 | `fe_csv_import_export_import_persist_result`    | `$result, $post_data, $context`     | Modify post persistence result     |
 | `fe_csv_import_export_taxonomy_term_resolution` | `$term_ids, $term_value, $taxonomy` | Customize taxonomy term resolution |
diff --git a/AGENT.md b/AGENT.md
index c15162e..23d2de6 100644
--- a/AGENT.md
+++ b/AGENT.md
@@ -8,7 +8,7 @@
 **FE CSV Import & Export** is a WordPress plugin for CSV import/export.
 Supports custom post types, custom taxonomies, and custom fields.
 
-- **Version**: 0.9.9
+- **Version**: 1.0.0
 - **License**: GPL-2.0+
 - **PHP**: >= 8.1 (recommended)
 - **Repository**: https://github.com/firstelementjp/fe-csv-import-export
diff --git a/README.md b/README.md
index 02bfddd..c37b436 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 ![FE CSV Import & Export Banner](https://github.com/firstelementjp/fe-csv-import-export/blob/main/assets/images/img-sns-banner-80.jpg?raw=true)
 
-[![Version](https://img.shields.io/badge/version-0.9.9.4-green.svg)](https://github.com/firstelementjp/fe-csv-import-export/releases)
+[![Version](https://img.shields.io/badge/version-1.0.0-green.svg)](https://github.com/firstelementjp/fe-csv-import-export/releases)
 [![License](https://img.shields.io/badge/License-GPLv2%2B-blue.svg)](https://www.gnu.org/licenses/gpl-2.0.html)
 [![WordPress](https://img.shields.io/badge/WordPress-6.6%2B-blue.svg)](https://wordpress.org/)
 [![Ask DeepWiki](https://deepwiki.com/badge.svg)](https://deepwiki.com/firstelementjp/fe-csv-import-export)
@@ -15,12 +15,11 @@ For end-user guides and full documentation, see the links below.
 
 ## ✨ Recent Highlights
 
-- Bundled JavaScript files to reduce HTTP requests and improve page load performance
-- Updated export batch planner to use memory_limit for dynamic batch size calculation
-- Reduced memory usage for large CSV imports by streaming batch reads and reusing file offsets
-- Improved import log tab behavior and preserved recent logs at completion
-- Fixed CSV quote parsing for edge cases involving backslash-escaped double quotes in legacy data
-- Cleaned up local release workflow so `test-release` and generated minified assets do not remain tracked in Git
+- Taxonomy optimization for unchanged terms significantly reduces processing time for update-heavy imports
+- Increased default import batch size from 100 to 500 rows to reduce AJAX overhead
+- Added configurable batch size limit filter for per-site customization
+- Detailed import profiling with WP_DEBUG batch profile logging for performance analysis
+- Fixed JavaScript ES module import syntax to resolve browser compatibility issues
 
 ## 📖 Overview
 
diff --git a/assets/js/fe-csv-import-export-main.js b/assets/js/fe-csv-import-export-main.js
index 5f52aa6..a78d621 100644
--- a/assets/js/fe-csv-import-export-main.js
+++ b/assets/js/fe-csv-import-export-main.js
@@ -5,20 +5,6 @@
  *
  */
 
-// Import core modules
-import './fe-csv-import-export-core.js';
-
-// Import export modules
-import './export/fe-csv-import-export/ajax.js';
-import './export/fe-csv-import-export/download.js';
-import './export/fe-csv-import-export/form.js';
-import './export/fe-csv-import-export/ui.js';
-import './export/fe-csv-import-export/logs.js';
-import './fe-csv-import-export-export-unified.js';
-import './export/fe-csv-import-export/original.js';
-import './fe-csv-import-export-import.js';
-import './fe-csv-import-export-license.js';
-
 /**
  * Bootstrap FE CSV Import & Export admin scripts when the DOM is ready.
  */
diff --git a/docs/README.md b/docs/README.md
index 159d17a..6635d3f 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -5,7 +5,7 @@
 > CSV import/export for WordPress with localized admin UI, automatic batch processing, and developer extensibility.
 
 [![License](https://img.shields.io/badge/license-GPL--2.0%2B-blue.svg)](legal.md)
-[![Version](https://img.shields.io/badge/version-0.9.9.4-green.svg)](https://github.com/firstelementjp/fe-csv-import-export/releases)
+[![Version](https://img.shields.io/badge/version-1.0.0-green.svg)](https://github.com/firstelementjp/fe-csv-import-export/releases)
 [![WordPress](https://img.shields.io/badge/WordPress-6.6%2B-blue.svg)](https://wordpress.org/)
 
 FE CSV Import & Export is a WordPress plugin for importing and exporting post data as CSV from the admin area.
@@ -29,11 +29,11 @@ FE CSV Import & Export is a WordPress plugin for importing and exporting post da
 
 ## 📥 Download
 
-[Download fe-csv-import-export-0.9.9.4.zip](https://github.com/firstelementjp/fe-csv-import-export/releases/download/v0.9.9.4/fe-csv-import-export-0.9.9.4.zip){: .download-btn }
+[Download fe-csv-import-export-1.0.0.zip](https://github.com/firstelementjp/fe-csv-import-export/releases/download/v1.0.0/fe-csv-import-export-1.0.0.zip){: .download-btn }
 
 ## 🚀 Quick Start
 
-1. Download `fe-csv-import-export-0.9.9.4.zip`
+1. Download `fe-csv-import-export-1.0.0.zip`
 2. Upload and activate the plugin in WordPress
 3. Open **Tools → FE CSV Import & Export**
 4. Run a small test import or export first
diff --git a/docs/changes.md b/docs/changes.md
index cabf724..137ae0c 100644
--- a/docs/changes.md
+++ b/docs/changes.md
@@ -1,5 +1,20 @@
 # 📋 Changelog
 
+## [1.0.0] - 2026-06-02
+
+### 🚀 Performance Improvements
+
+- **Taxonomy optimization for unchanged terms** - Import now skips `wp_set_post_terms()` calls when taxonomy terms are unchanged, significantly reducing processing time for update-heavy imports.
+- **Increased default batch size** - Default import batch size increased from 100 to 500 rows, reducing AJAX overhead for large imports.
+- **Configurable batch size limit** - New `fe_csv_import_export_import_max_batch_size` filter allows per-site customization of the maximum batch size.
+- **Detailed import profiling** - Added granular profiling for import phases (preload, row context, row processor, meta/taxonomy preparation and application) with WP_DEBUG batch profile logging.
+
+### 🛠️ Bug Fixes
+
+- **Fixed JavaScript ES module import syntax** - Removed static ES module imports from main JS file to resolve browser syntax errors.
+
+---
+
 ## [0.9.9.4] - 2026-05-27
 
 ### 🚀 Performance Improvements
diff --git a/docs/install.md b/docs/install.md
index 004f4eb..65f8c05 100644
--- a/docs/install.md
+++ b/docs/install.md
@@ -10,7 +10,7 @@
 
 ## Manual Installation
 
-1. [Download latest version (v0.9.9.4)](https://github.com/firstelementjp/fe-csv-import-export/releases/download/v0.9.9.4/fe-csv-import-export-0.9.9.4.zip)
+1. [Download latest version (v1.0.0)](https://github.com/firstelementjp/fe-csv-import-export/releases/download/v1.0.0/fe-csv-import-export-1.0.0.zip)
 2. Extract the downloaded ZIP file
 3. Upload `fe-csv-import-export` folder to `/wp-content/plugins/`
 4. Navigate to **Plugins** in WordPress admin
diff --git a/fe-csv-import-export.php b/fe-csv-import-export.php
index 8715aa8..29fd955 100644
--- a/fe-csv-import-export.php
+++ b/fe-csv-import-export.php
@@ -3,7 +3,7 @@
  * Plugin Name:  FE CSV Import & Export
  * Plugin URI:   https://github.com/firstelementjp/fe-csv-import-export
  * Description:  Simple yet powerful CSV import/export plugin for WordPress. Supports custom post types, custom taxonomies, and custom fields.
- * Version:      0.9.9.4
+ * Version:      1.0.0
  * Author:       FirstElement K.K., Daijiro Miyazawa
  * Author URI:   https://www.firstelement.co.jp/
  * License:      GPL-2.0+
@@ -20,7 +20,7 @@
 }
 
 // Define plugin constants.
-define( 'FE_CSV_IMPORT_EXPORT_VERSION', '0.9.9.4' );
+define( 'FE_CSV_IMPORT_EXPORT_VERSION', '1.0.0' );
 define( 'FE_CSV_IMPORT_EXPORT_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
 define( 'FE_CSV_IMPORT_EXPORT_PLUGIN_URL', plugin_dir_url( __FILE__ ) );
 define( 'FE_CSV_IMPORT_EXPORT_BASENAME', plugin_basename( __FILE__ ) );
diff --git a/includes/admin/class-fe-csv-import-export-admin-assets.php b/includes/admin/class-fe-csv-import-export-admin-assets.php
index d56cda5..ee463e1 100644
--- a/includes/admin/class-fe-csv-import-export-admin-assets.php
+++ b/includes/admin/class-fe-csv-import-export-admin-assets.php
@@ -73,8 +73,12 @@ public function enqueue_scripts( $hook ) {
 				? (bool) FE_CSV_Import_Export_Settings_Helper::get( 'advanced', 'enable_logs', true )
 				: true;
 
+			// Temporarily force individual files for both debug and production modes
+			// to resolve dialog opening issue in production mode
+			$force_individual_files = true;
+
 			// Use bundled script for production, individual files for debug mode
-			if ( $debug_mode ) {
+			if ( $debug_mode || $force_individual_files ) {
 				// Debug mode: load individual files for easier debugging
 				$script_url = static function ( $relative_path ) use ( $suffix ) {
 					$min_path      = preg_replace( '/\.js$/', $suffix . '.js', $relative_path );
@@ -315,7 +319,8 @@ public function enqueue_scripts( $hook ) {
 			}
 
 			// Localize script (use the main script handle based on mode)
-			$main_script_handle = $debug_mode ? 'fe-csv-import-export-core' : 'fe-csv-import-export-admin';
+			// When forcing individual files, always use core handle
+			$main_script_handle = ( $debug_mode || $force_individual_files ) ? 'fe-csv-import-export-core' : 'fe-csv-import-export-admin';
 
 			wp_localize_script(
 				$main_script_handle,
diff --git a/includes/import/class-fe-csv-import-export-ajax-import-batch-planner.php b/includes/import/class-fe-csv-import-export-ajax-import-batch-planner.php
index 0546077..286c2f8 100644
--- a/includes/import/class-fe-csv-import-export-ajax-import-batch-planner.php
+++ b/includes/import/class-fe-csv-import-export-ajax-import-batch-planner.php
@@ -29,17 +29,82 @@ class FE_CSV_Import_Export_Ajax_Import_Batch_Planner {
 	 * @return int Batch size.
 	 */
 	public function get_import_batch_size( int $total_rows, array $config ): int {
-		$max_execution_time = ini_get( 'max_execution_time' );
-		$max_execution_time = $max_execution_time ? (int) $max_execution_time : 30;
-		$max_execution_time = max( 1, $max_execution_time );
+		if ( $total_rows <= 0 ) {
+			return 1;
+		}
+
+		$max_execution_time = $this->get_max_execution_time();
+		$safe_time_limit    = $max_execution_time * 0.8;
+		$avg_time_per_row   = 0.02;
+		$time_based_batch   = max( 1, (int) floor( $safe_time_limit / $avg_time_per_row ) );
 
-		$safe_time_limit      = $max_execution_time * 0.5;
-		$avg_time_per_row     = 0.35;
-		$time_based_batch     = max( 1, (int) floor( $safe_time_limit / $avg_time_per_row ) );
-		$optimized_batch_size = max( 10, min( 50, $time_based_batch ) );
+		$memory_limit       = $this->convert_memory_limit_to_bytes( (string) ini_get( 'memory_limit' ) );
+		$memory_limit       = max( 64 * 1024 * 1024, $memory_limit );
+		$available_memory   = max( 16 * 1024 * 1024, $memory_limit - ( 48 * 1024 * 1024 ) );
+		$memory_per_row     = 128 * 1024;
+		$memory_based_batch = max( 1, (int) floor( $available_memory / $memory_per_row ) );
 
-		$base_batch_size = max( 1, min( $total_rows, $optimized_batch_size ) );
+		$optimized_batch_size = min( $time_based_batch, $memory_based_batch, $total_rows );
+		$max_batch_size       = (int) apply_filters( 'fe_csv_import_export_import_max_batch_size', 500, $total_rows, $config );
+		$max_batch_size       = max( 10, $max_batch_size );
+		$base_batch_size      = max( 10, min( $max_batch_size, $optimized_batch_size ) );
+		$base_batch_size      = min( $total_rows, $base_batch_size );
 
 		return (int) apply_filters( 'fe_csv_import_export_import_batch_size', $base_batch_size, $total_rows, $config );
 	}
+
+	/**
+	 * Get max execution time with a safe fallback.
+	 *
+	 * @since 0.9.8
+	 * @return int Max execution time in seconds.
+	 */
+	private function get_max_execution_time(): int {
+		$max_execution_time = ini_get( 'max_execution_time' );
+		$max_execution_time = false === $max_execution_time ? 30 : (int) $max_execution_time;
+
+		if ( $max_execution_time <= 0 ) {
+			return 120;
+		}
+
+		return max( 1, $max_execution_time );
+	}
+
+	/**
+	 * Convert memory limit string to bytes.
+	 *
+	 * @since 0.9.8
+	 * @param string $memory_limit Memory limit string.
+	 * @return int Memory limit in bytes.
+	 */
+	private function convert_memory_limit_to_bytes( string $memory_limit ): int {
+		$memory_limit = strtoupper( trim( $memory_limit ) );
+
+		if ( '-1' === $memory_limit ) {
+			return PHP_INT_MAX;
+		}
+
+		if ( '' === $memory_limit ) {
+			return 128 * 1024 * 1024;
+		}
+
+		$unit  = substr( $memory_limit, -1 );
+		$value = (int) substr( $memory_limit, 0, -1 );
+
+		switch ( $unit ) {
+			case 'G':
+				$value *= 1024 * 1024 * 1024;
+				break;
+			case 'M':
+				$value *= 1024 * 1024;
+				break;
+			case 'K':
+				$value *= 1024;
+				break;
+			default:
+				$value = (int) $memory_limit;
+		}
+
+		return $value > 0 ? $value : 128 * 1024 * 1024;
+	}
 }
diff --git a/includes/import/class-fe-csv-import-export-import-batch-processor.php b/includes/import/class-fe-csv-import-export-import-batch-processor.php
index 173723b..04cf89f 100644
--- a/includes/import/class-fe-csv-import-export-import-batch-processor.php
+++ b/includes/import/class-fe-csv-import-export-import-batch-processor.php
@@ -220,6 +220,32 @@ protected function initialize_counters(): array {
 			'errors'          => 0,
 			'dry_run_log'     => [],
 			'dry_run_details' => [],
+			'import_profile'  => $this->initialize_import_profile(),
+		];
+	}
+
+	/**
+	 * Initialize import profile counters.
+	 *
+	 * @since 0.9.9.5
+	 * @return array<string, float|int>
+	 */
+	private function initialize_import_profile(): array {
+		return [
+			'preload'               => 0.0,
+			'row_context'           => 0.0,
+			'row_processor'         => 0.0,
+			'success_log'           => 0.0,
+			'success_counter_guid'  => 0.0,
+			'prepare_meta_tax'      => 0.0,
+			'compat_hooks'          => 0.0,
+			'meta_apply'            => 0.0,
+			'tax_apply'             => 0.0,
+			'tax_resolve'           => 0.0,
+			'tax_set_terms'         => 0.0,
+			'tax_set_terms_calls'   => 0,
+			'tax_set_terms_skipped' => 0,
+			'rows_profiled'         => 0,
 		];
 	}
 
@@ -255,6 +281,7 @@ private function process_batch_import( array $config, array $csv_data, array &$c
 		}
 
 		if ( isset( $csv_data['batch_lines'] ) && is_array( $csv_data['batch_lines'] ) ) {
+			$preload_started_at            = microtime( true );
 			$current_batch_data            = array_map(
 				function ( string $line ) use ( $csv_data ): array {
 					return $this->get_csv_util()->parse_csv_row( $line, (string) $csv_data['delimiter'] );
@@ -270,6 +297,7 @@ function ( string $line ) use ( $csv_data ): array {
 					'post_type' => (string) ( $config['post_type'] ?? 'post' ),
 				]
 			);
+			$counters['import_profile']['preload'] += microtime( true ) - $preload_started_at;
 		}
 
 		wp_defer_term_counting( true );
@@ -322,11 +350,11 @@ protected function validate_id_column_or_send_error( array $config, array $csv_d
 	 * Run the batch loop.
 	 *
 	 * @since 0.9.8
-	 * @param wpdb                           $wpdb WordPress database handler.
-	 * @param array                          $config Import configuration.
-	 * @param array                          $csv_data Parsed CSV data.
-	 * @param array                          $allowed_post_fields Allowed post fields.
-	 * @param array                          $counters Counters (by reference).
+	 * @param wpdb                                      $wpdb WordPress database handler.
+	 * @param array                                     $config Import configuration.
+	 * @param array                                     $csv_data Parsed CSV data.
+	 * @param array                                     $allowed_post_fields Allowed post fields.
+	 * @param array                                     $counters Counters (by reference).
 	 * @param FE_CSV_Import_Export_Import_Row_Context   $row_context_util Row context util.
 	 * @param FE_CSV_Import_Export_Import_Row_Processor $row_processor_util Row processor util.
 	 * @param FE_CSV_Import_Export_Import_Persister     $persister_util Persister util.
@@ -348,6 +376,7 @@ protected function process_batch_loop(
 		$import_session = (string) ( $config['import_session'] ?? '' );
 		$batch_lines    = isset( $csv_data['batch_lines'] ) && is_array( $csv_data['batch_lines'] ) ? $csv_data['batch_lines'] : [];
 		$batch_count    = count( $batch_lines );
+		$batch_items    = [];
 		for ( $i = 0; $i < $batch_count; $i++ ) {
 			if ( '' !== $import_session && $this->get_cancel_manager()->is_cancelled( $import_session ) ) {
 				break;
@@ -363,25 +392,30 @@ protected function process_batch_loop(
 				$row_context_util,
 				$row_processor_util,
 				$persister_util,
-				$meta_tax_util
+				$meta_tax_util,
+				$batch_items
 			);
 		}
+
+		$context = $this->build_row_processing_context( $config, $csv_data, $csv_data['headers'], $allowed_post_fields );
+		$meta_tax_util->apply_prepared_meta_and_taxonomies_for_batch( $wpdb, $batch_items, $context, $counters['dry_run_log'], $counters['import_profile'] );
 	}
 
 	/**
 	 * Import loop iteration logic
 	 *
 	 * @since 0.9.8
-	 * @param wpdb                           $wpdb WordPress database handler.
-	 * @param array                          $config Import configuration.
-	 * @param array                          $csv_data Parsed CSV data.
-	 * @param array                          $allowed_post_fields Allowed post fields.
-	 * @param int                            $index Row index.
-	 * @param array                          $counters Counters (by reference).
+	 * @param wpdb                                      $wpdb WordPress database handler.
+	 * @param array                                     $config Import configuration.
+	 * @param array                                     $csv_data Parsed CSV data.
+	 * @param array                                     $allowed_post_fields Allowed post fields.
+	 * @param int                                       $index Row index.
+	 * @param array                                     $counters Counters (by reference).
 	 * @param FE_CSV_Import_Export_Import_Row_Context   $row_context_util Row context util.
 	 * @param FE_CSV_Import_Export_Import_Row_Processor $row_processor_util Row processor util.
 	 * @param FE_CSV_Import_Export_Import_Persister     $persister_util Persister util.
 	 * @param FE_CSV_Import_Export_Import_Meta_Tax      $meta_tax_util Meta/tax util.
+	 * @param array                                     $batch_items Prepared batch items.
 	 * @return void
 	 */
 	private function process_import_loop_iteration(
@@ -394,7 +428,8 @@ private function process_import_loop_iteration(
 		FE_CSV_Import_Export_Import_Row_Context $row_context_util,
 		FE_CSV_Import_Export_Import_Row_Processor $row_processor_util,
 		FE_CSV_Import_Export_Import_Persister $persister_util,
-		FE_CSV_Import_Export_Import_Meta_Tax $meta_tax_util
+		FE_CSV_Import_Export_Import_Meta_Tax $meta_tax_util,
+		array &$batch_items
 	): void {
 		$lines             = $csv_data['batch_lines'];
 		$delimiter         = $csv_data['delimiter'];
@@ -408,39 +443,41 @@ private function process_import_loop_iteration(
 			return;
 		}
 
-		// Use Ajax_Import's original row processing logic.
-		$row_context = $this->build_import_row_context_from_config( $wpdb, $row_context_util, $config, $line, $delimiter, $headers, $allowed_post_fields, $parsed_data );
+		$row_context_started_at                     = microtime( true );
+		$row_context                                = $this->build_import_row_context_from_config( $wpdb, $row_context_util, $config, $line, $delimiter, $headers, $allowed_post_fields, $parsed_data );
+		$counters['import_profile']['row_context'] += microtime( true ) - $row_context_started_at;
 		if ( null === $row_context ) {
 			return;
 		}
 
 		$context = $this->build_row_processing_context( $config, $csv_data, $headers, $allowed_post_fields );
 
-		// Use the original row processor utility.
+		$row_processor_started_at = microtime( true );
 		$row_processor_util->process_row_context_with_persister(
 			$wpdb,
 			$row_context,
 			$context,
 			$counters,
 			$persister_util,
-			function ( wpdb $wpdb, int $post_id, bool $is_update, array $context, array &$counters ) use ( $meta_tax_util ): void {
-				$this->handle_successful_row_import( $wpdb, $post_id, $is_update, $context, $counters, $meta_tax_util );
+			function ( wpdb $wpdb, int $post_id, bool $is_update, array $context, array &$counters ) use ( $meta_tax_util, &$batch_items ): void {
+				$this->handle_successful_row_import( $wpdb, $post_id, $is_update, $context, $counters, $meta_tax_util, $batch_items );
 			}
 		);
+		$counters['import_profile']['row_processor'] += microtime( true ) - $row_processor_started_at;
 	}
 
 	/**
 	 * Row context building logic
 	 *
 	 * @since 0.9.8
-	 * @param wpdb                         $wpdb WordPress database handler.
+	 * @param wpdb                                    $wpdb WordPress database handler.
 	 * @param FE_CSV_Import_Export_Import_Row_Context $row_context_util Row context util.
-	 * @param array                        $config Import configuration.
-	 * @param string                       $line CSV line.
-	 * @param string                       $delimiter CSV delimiter.
-	 * @param array                        $headers CSV headers.
-	 * @param array                        $allowed_post_fields Allowed post fields.
-	 * @param array                        $parsed_data Parsed CSV row data.
+	 * @param array                                   $config Import configuration.
+	 * @param string                                  $line CSV line.
+	 * @param string                                  $delimiter CSV delimiter.
+	 * @param array                                   $headers CSV headers.
+	 * @param array                                   $allowed_post_fields Allowed post fields.
+	 * @param array                                   $parsed_data Parsed CSV row data.
 	 * @return array|null Row context or null if invalid.
 	 */
 	protected function build_import_row_context_from_config( wpdb $wpdb, FE_CSV_Import_Export_Import_Row_Context $row_context_util, array $config, string $line, string $delimiter, array $headers, array $allowed_post_fields, array $parsed_data = [] ): ?array {
@@ -484,22 +521,22 @@ protected function build_row_processing_context( array $config, array $csv_data,
 	 * Successful row import handling logic.
 	 *
 	 * @since 0.9.8
-	 * @param wpdb                      $wpdb WordPress database object.
-	 * @param int                       $post_id Post ID.
-	 * @param bool                      $is_update Whether this was an update.
-	 * @param array                     $context Row processing context.
-	 * @param array                     $counters Counters (by reference).
+	 * @param wpdb                                 $wpdb WordPress database object.
+	 * @param int                                  $post_id Post ID.
+	 * @param bool                                 $is_update Whether this was an update.
+	 * @param array                                $context Row processing context.
+	 * @param array                                $counters Counters (by reference).
 	 * @param FE_CSV_Import_Export_Import_Meta_Tax $meta_tax_util Meta/tax util.
+	 * @param array                                $batch_items Prepared batch items.
 	 * @return void
 	 */
-	protected function handle_successful_row_import( wpdb $wpdb, int $post_id, bool $is_update, array $context, array &$counters, FE_CSV_Import_Export_Import_Meta_Tax $meta_tax_util ): void {
-		$headers                    = $context['headers'];
-		$data                       = $context['data'];
-		$allowed_post_fields        = $context['allowed_post_fields'];
-		$taxonomy_format            = $context['taxonomy_format'];
-		$taxonomy_format_validation = $context['taxonomy_format_validation'];
-		$dry_run                    = $context['dry_run'];
-		$should_generate_logs       = isset( $context['append_log'] ) && is_callable( $context['append_log'] );
+	protected function handle_successful_row_import( wpdb $wpdb, int $post_id, bool $is_update, array $context, array &$counters, FE_CSV_Import_Export_Import_Meta_Tax $meta_tax_util, array &$batch_items ): void {
+		$headers                = $context['headers'];
+		$data                   = $context['data'];
+		$allowed_post_fields    = $context['allowed_post_fields'];
+		$dry_run                = $context['dry_run'];
+		$should_generate_logs   = isset( $context['append_log'] ) && is_callable( $context['append_log'] );
+		$success_log_started_at = microtime( true );
 
 		if ( $should_generate_logs ) {
 			$row_number = $context['start_row'] + $counters['processed'] + 1; // Correct row number from context.
@@ -526,25 +563,26 @@ protected function handle_successful_row_import( wpdb $wpdb, int $post_id, bool
 
 			call_user_func( $context['append_log'], $detail );
 		}
+		$counters['import_profile']['success_log'] += microtime( true ) - $success_log_started_at;
 
+		$success_counter_started_at = microtime( true );
 		$this->get_row_processor_util()->apply_success_counters_and_guid_without_callbacks(
 			$wpdb,
 			$post_id,
 			$is_update,
 			$counters
 		);
+		$counters['import_profile']['success_counter_guid'] += microtime( true ) - $success_counter_started_at;
 
-		$result = $meta_tax_util->process_meta_and_taxonomies_for_row_with_args(
-			$wpdb,
+		$prepare_started_at = microtime( true );
+		$result             = $meta_tax_util->prepare_meta_and_taxonomies_for_row_with_args(
 			$post_id,
 			$headers,
 			$data,
-			$allowed_post_fields,
-			$taxonomy_format,
-			$taxonomy_format_validation,
-			$dry_run,
-			$counters
+			$allowed_post_fields
 		);
+		$batch_items[]      = $result;
+		$counters['import_profile']['prepare_meta_tax'] += microtime( true ) - $prepare_started_at;
 
 		$prepare_args         = [
 			'headers'   => $headers,
@@ -553,11 +591,14 @@ protected function handle_successful_row_import( wpdb $wpdb, int $post_id, bool
 			'post_type' => $context['post_type'] ?? 'post',
 			'dry_run'   => $dry_run,
 		];
+		$hooks_started_at     = microtime( true );
 		$prepared_meta_fields = apply_filters( 'fe_csv_import_export_prepare_import_fields', $result['meta_fields'], $post_id, $prepare_args );
 		do_action( 'fe_csv_import_export_import_phase_map_prepared', $post_id, $prepared_meta_fields, $prepare_args );
 
 		do_action( 'fe_csv_import_export_import_phase_post_persist', $post_id, $prepared_meta_fields, $prepare_args );
 		do_action( 'fe_csv_import_export_process_custom_fields', $post_id, $prepared_meta_fields );
+		$counters['import_profile']['compat_hooks'] += microtime( true ) - $hooks_started_at;
+		++$counters['import_profile']['rows_profiled'];
 	}
 
 	/**
diff --git a/includes/import/class-fe-csv-import-export-import-meta-tax.php b/includes/import/class-fe-csv-import-export-import-meta-tax.php
index 22ccef5..e7d383b 100644
--- a/includes/import/class-fe-csv-import-export-import-meta-tax.php
+++ b/includes/import/class-fe-csv-import-export-import-meta-tax.php
@@ -178,6 +178,83 @@ public function process_meta_and_taxonomies_for_row_with_args(
 		];
 	}
 
+	/**
+	 * Prepare meta fields and taxonomies for a post using explicit arguments.
+	 *
+	 * @since 0.9.0
+	 * @param int               $post_id Post ID.
+	 * @param array<int,string> $headers CSV headers.
+	 * @param array<int,string> $data CSV row data.
+	 * @param array<int,string> $allowed_post_fields Allowed WP post fields.
+	 * @return array{
+	 *   post_id: int,
+	 *   meta_fields: array<string,string>,
+	 *   taxonomies:  array<string,array<int,string>>,
+	 *   context_data: array<int,string>
+	 * }
+	 */
+	public function prepare_meta_and_taxonomies_for_row_with_args(
+		int $post_id,
+		array $headers,
+		array $data,
+		array $allowed_post_fields
+	): array {
+		$collected_fields = $this->collect_taxonomies_and_meta_fields_from_row( $headers, $data, $allowed_post_fields );
+
+		$collected_fields = apply_filters(
+			'fe_csv_import_export_import_field_mapping',
+			$collected_fields,
+			$headers,
+			$data,
+			$allowed_post_fields
+		);
+		do_action(
+			'fe_csv_import_export_import_phase_map',
+			$collected_fields,
+			$headers,
+			$data,
+			$allowed_post_fields
+		);
+
+		return [
+			'post_id'      => $post_id,
+			'meta_fields'  => $collected_fields['meta_fields'],
+			'taxonomies'   => $collected_fields['taxonomies'],
+			'context_data' => $data,
+		];
+	}
+
+	/**
+	 * Apply prepared meta fields and taxonomies for a batch.
+	 *
+	 * @since 0.9.0
+	 * @param wpdb       $wpdb WordPress database handler.
+	 * @param array      $items Prepared batch items.
+	 * @param array      $context Context values for row processing.
+	 * @param array      $dry_run_log Dry run log.
+	 * @param array|null $profile Import profile counters.
+	 * @return void
+	 */
+	public function apply_prepared_meta_and_taxonomies_for_batch(
+		wpdb $wpdb,
+		array $items,
+		array $context,
+		array &$dry_run_log,
+		?array &$profile = null
+	): void {
+		if ( null === $profile ) {
+			$profile = [];
+		}
+
+		$meta_started_at = microtime( true );
+		$this->apply_prepared_meta_fields_for_batch( $wpdb, $items, $context, $dry_run_log );
+		$profile['meta_apply'] = (float) ( $profile['meta_apply'] ?? 0.0 ) + microtime( true ) - $meta_started_at;
+
+		$tax_started_at = microtime( true );
+		$this->apply_prepared_taxonomies_for_batch( $wpdb, $items, $context, $dry_run_log, $profile );
+		$profile['tax_apply'] = (float) ( $profile['tax_apply'] ?? 0.0 ) + microtime( true ) - $tax_started_at;
+	}
+
 	/**
 	 * Collect taxonomy fields from a CSV row.
 	 *
@@ -219,20 +296,6 @@ public function collect_taxonomy_fields_from_row( array $headers, array $data ):
 			$taxonomy_name                = substr( $header_name_normalized, 4 ); // Remove 'tax_'.
 			$taxonomies[ $taxonomy_name ] = $terms;
 
-			if ( taxonomy_exists( $taxonomy_name ) ) {
-				$term_ids = [];
-				foreach ( $terms as $term_name ) {
-					if ( ! empty( $term_name ) ) {
-						$term = get_term_by( 'name', $term_name, $taxonomy_name );
-						if ( $term ) {
-							$term_ids[] = $term->term_id;
-						}
-					}
-				}
-				if ( ! empty( $term_ids ) ) {
-					$taxonomy_term_ids[ $taxonomy_name ] = $term_ids;
-				}
-			}
 		}
 
 		return [
@@ -410,6 +473,242 @@ public function apply_taxonomies_for_post(
 		$this->taxonomy_writer->apply_taxonomies_for_post( $wpdb, $post_id, $taxonomies, $context, $dry_run_log );
 	}
 
+	/**
+	 * Apply prepared taxonomies for a batch.
+	 *
+	 * @since 0.9.0
+	 * @param wpdb       $wpdb WordPress DB instance.
+	 * @param array      $items Prepared batch items.
+	 * @param array      $context Context values for row processing.
+	 * @param array      $dry_run_log Dry run log.
+	 * @param array|null $profile Import profile counters.
+	 * @return void
+	 */
+	private function apply_prepared_taxonomies_for_batch(
+		wpdb $wpdb,
+		array $items,
+		array $context,
+		array &$dry_run_log,
+		?array &$profile = null
+	): void {
+		if ( null === $profile ) {
+			$profile = [];
+		}
+
+		$dry_run                    = (bool) ( $context['dry_run'] ?? false );
+		$taxonomy_format            = (string) ( $context['taxonomy_format'] ?? 'name' );
+		$taxonomy_format_validation = isset( $context['taxonomy_format_validation'] ) && is_array( $context['taxonomy_format_validation'] ) ? $context['taxonomy_format_validation'] : [];
+		$term_id_cache              = [];
+		$existing_term_map          = $dry_run ? [] : $this->get_existing_term_ids_for_batch( $wpdb, $items );
+
+		foreach ( $items as $item ) {
+			if ( ! is_array( $item ) ) {
+				continue;
+			}
+
+			$post_id    = (int) ( $item['post_id'] ?? 0 );
+			$taxonomies = isset( $item['taxonomies'] ) && is_array( $item['taxonomies'] ) ? $item['taxonomies'] : [];
+			if ( empty( $taxonomies ) || ( $post_id <= 0 && ! $dry_run ) ) {
+				continue;
+			}
+
+			foreach ( $taxonomies as $taxonomy => $terms ) {
+				if ( ! is_string( $taxonomy ) || ! is_array( $terms ) || empty( $terms ) ) {
+					continue;
+				}
+
+				$resolve_started_at     = microtime( true );
+				$term_ids               = $this->resolve_taxonomy_term_ids_with_cache(
+					$taxonomy,
+					$terms,
+					$taxonomy_format,
+					$taxonomy_format_validation,
+					$term_id_cache
+				);
+				$profile['tax_resolve'] = (float) ( $profile['tax_resolve'] ?? 0.0 ) + microtime( true ) - $resolve_started_at;
+
+				if ( ! $dry_run && $this->are_taxonomy_terms_unchanged( $existing_term_map, $post_id, $taxonomy, $term_ids ) ) {
+					$profile['tax_set_terms_skipped'] = (int) ( $profile['tax_set_terms_skipped'] ?? 0 ) + 1;
+					continue;
+				}
+
+				$set_terms_started_at = microtime( true );
+				$this->apply_taxonomy_terms_to_post( $post_id, $taxonomy, $term_ids, $dry_run, $dry_run_log );
+				$profile['tax_set_terms']       = (float) ( $profile['tax_set_terms'] ?? 0.0 ) + microtime( true ) - $set_terms_started_at;
+				$profile['tax_set_terms_calls'] = (int) ( $profile['tax_set_terms_calls'] ?? 0 ) + 1;
+			}
+		}
+	}
+
+	/**
+	 * Get existing taxonomy term IDs for all post/taxonomy pairs in a batch.
+	 *
+	 * @since 0.9.9.5
+	 * @param wpdb  $wpdb WordPress DB instance.
+	 * @param array $items Prepared batch items.
+	 * @return array<int, array<string, array<int, int>>>
+	 */
+	private function get_existing_term_ids_for_batch( wpdb $wpdb, array $items ): array {
+		$post_ids   = [];
+		$taxonomies = [];
+
+		foreach ( $items as $item ) {
+			if ( ! is_array( $item ) ) {
+				continue;
+			}
+
+			$post_id = (int) ( $item['post_id'] ?? 0 );
+			if ( $post_id <= 0 ) {
+				continue;
+			}
+
+			$item_taxonomies = isset( $item['taxonomies'] ) && is_array( $item['taxonomies'] ) ? $item['taxonomies'] : [];
+			foreach ( $item_taxonomies as $taxonomy => $terms ) {
+				if ( ! is_string( $taxonomy ) || ! is_array( $terms ) || empty( $terms ) ) {
+					continue;
+				}
+
+				$post_ids[]   = $post_id;
+				$taxonomies[] = $taxonomy;
+			}
+		}
+
+		$post_ids   = array_values( array_unique( array_map( 'intval', $post_ids ) ) );
+		$taxonomies = array_values( array_unique( array_map( 'strval', $taxonomies ) ) );
+		if ( empty( $post_ids ) || empty( $taxonomies ) ) {
+			return [];
+		}
+
+		$post_placeholders     = implode( ',', array_fill( 0, count( $post_ids ), '%d' ) );
+		$taxonomy_placeholders = implode( ',', array_fill( 0, count( $taxonomies ), '%s' ) );
+		$query_args            = array_merge( $post_ids, $taxonomies );
+
+		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
+		$sql = "SELECT tr.object_id, tt.taxonomy, tt.term_id
+			FROM {$wpdb->term_relationships} tr
+			INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
+			WHERE tr.object_id IN ({$post_placeholders})
+			AND tt.taxonomy IN ({$taxonomy_placeholders})";
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.NotPrepared
+		$rows = $wpdb->get_results( $wpdb->prepare( $sql, $query_args ), ARRAY_A );
+		if ( empty( $rows ) ) {
+			return [];
+		}
+
+		$existing_term_map = [];
+		foreach ( $rows as $row ) {
+			$post_id  = (int) ( $row['object_id'] ?? 0 );
+			$taxonomy = (string) ( $row['taxonomy'] ?? '' );
+			$term_id  = (int) ( $row['term_id'] ?? 0 );
+			if ( $post_id <= 0 || '' === $taxonomy || $term_id <= 0 ) {
+				continue;
+			}
+
+			if ( ! isset( $existing_term_map[ $post_id ] ) ) {
+				$existing_term_map[ $post_id ] = [];
+			}
+			if ( ! isset( $existing_term_map[ $post_id ][ $taxonomy ] ) ) {
+				$existing_term_map[ $post_id ][ $taxonomy ] = [];
+			}
+
+			$existing_term_map[ $post_id ][ $taxonomy ][] = $term_id;
+		}
+
+		foreach ( $existing_term_map as $post_id => $taxonomy_terms ) {
+			foreach ( $taxonomy_terms as $taxonomy => $term_ids ) {
+				$existing_term_map[ $post_id ][ $taxonomy ] = $this->normalize_term_ids_for_comparison( $term_ids );
+			}
+		}
+
+		return $existing_term_map;
+	}
+
+	/**
+	 * Check whether taxonomy terms are unchanged for a post.
+	 *
+	 * @since 0.9.9.5
+	 * @param array  $existing_term_map Existing term IDs by post and taxonomy.
+	 * @param int    $post_id Post ID.
+	 * @param string $taxonomy Taxonomy name.
+	 * @param array  $term_ids Resolved term IDs.
+	 * @return bool Whether the terms are unchanged.
+	 */
+	private function are_taxonomy_terms_unchanged( array $existing_term_map, int $post_id, string $taxonomy, array $term_ids ): bool {
+		$existing_term_ids = isset( $existing_term_map[ $post_id ][ $taxonomy ] ) && is_array( $existing_term_map[ $post_id ][ $taxonomy ] )
+			? $existing_term_map[ $post_id ][ $taxonomy ]
+			: [];
+		$new_term_ids      = $this->normalize_term_ids_for_comparison( $term_ids );
+
+		return $existing_term_ids === $new_term_ids;
+	}
+
+	/**
+	 * Normalize term IDs for deterministic comparison.
+	 *
+	 * @since 0.9.9.5
+	 * @param array $term_ids Term IDs.
+	 * @return array<int, int>
+	 */
+	private function normalize_term_ids_for_comparison( array $term_ids ): array {
+		$term_ids = array_values(
+			array_unique(
+				array_filter(
+					array_map( 'intval', $term_ids ),
+					static function ( int $term_id ): bool {
+						return $term_id > 0;
+					}
+				)
+			)
+		);
+		sort( $term_ids, SORT_NUMERIC );
+
+		return $term_ids;
+	}
+
+	/**
+	 * Resolve taxonomy term IDs using a batch-local cache.
+	 *
+	 * @since 0.9.0
+	 * @param string             $taxonomy Taxonomy name.
+	 * @param array<int, string> $terms Term values.
+	 * @param string             $taxonomy_format Taxonomy format.
+	 * @param array              $taxonomy_format_validation Taxonomy format validation.
+	 * @param array              $term_id_cache Resolved term ID cache.
+	 * @return array<int, int>
+	 */
+	private function resolve_taxonomy_term_ids_with_cache(
+		string $taxonomy,
+		array $terms,
+		string $taxonomy_format,
+		array $taxonomy_format_validation,
+		array &$term_id_cache
+	): array {
+		$term_ids = [];
+		foreach ( $terms as $term_value ) {
+			$term_value = trim( (string) $term_value );
+			if ( '' === $term_value ) {
+				continue;
+			}
+
+			$cache_key = $taxonomy . "\n" . $taxonomy_format . "\n" . $term_value;
+			if ( ! array_key_exists( $cache_key, $term_id_cache ) ) {
+				$term_id_cache[ $cache_key ] = $this->resolve_term_ids_for_term_value(
+					$taxonomy,
+					$term_value,
+					$taxonomy_format,
+					$taxonomy_format_validation
+				);
+			}
+
+			foreach ( $term_id_cache[ $cache_key ] as $resolved_term_id ) {
+				$term_ids[] = (int) $resolved_term_id;
+			}
+		}
+
+		return array_values( array_unique( $term_ids ) );
+	}
+
 	/**
 	 * Resolve term IDs from a term value.
 	 *
@@ -552,6 +851,150 @@ public function apply_meta_fields_for_post(
 		}
 	}
 
+	/**
+	 * Apply prepared meta fields for a batch.
+	 *
+	 * @since 0.9.0
+	 * @param wpdb  $wpdb WordPress DB instance.
+	 * @param array $items Prepared batch items.
+	 * @param array $context Context values for row processing.
+	 * @param array $dry_run_log Dry run log.
+	 * @return void
+	 */
+	private function apply_prepared_meta_fields_for_batch(
+		wpdb $wpdb,
+		array $items,
+		array $context,
+		array &$dry_run_log
+	): void {
+		$dry_run     = (bool) ( $context['dry_run'] ?? false );
+		$delete_keys = [];
+		$insert_rows = [];
+
+		foreach ( $items as $item ) {
+			if ( ! is_array( $item ) ) {
+				continue;
+			}
+
+			$post_id     = (int) ( $item['post_id'] ?? 0 );
+			$meta_fields = isset( $item['meta_fields'] ) && is_array( $item['meta_fields'] ) ? $item['meta_fields'] : [];
+			if ( empty( $meta_fields ) || ( $post_id <= 0 && ! $dry_run ) ) {
+				continue;
+			}
+
+			foreach ( $meta_fields as $key => $value ) {
+				if ( '' === $value || null === $value ) {
+					continue;
+				}
+
+				if ( ! is_string( $value ) ) {
+					$value = maybe_serialize( $value );
+				}
+
+				if ( $dry_run ) {
+					$this->append_meta_dry_run_log( (string) $key, (string) $value, $dry_run_log );
+					continue;
+				}
+
+				$delete_keys[ $post_id . "\n" . $key ] = [
+					'post_id'  => $post_id,
+					'meta_key' => (string) $key, // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
+				];
+
+				$values = $this->get_csv_util()->split_pipe_separated_values( $value );
+				foreach ( array_map( 'trim', $values ) as $single_value ) {
+					if ( '' === $single_value ) {
+						continue;
+					}
+					$insert_rows[] = [
+						'post_id'    => $post_id,
+						'meta_key'   => (string) $key, // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
+						'meta_value' => $single_value, // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_value
+					];
+				}
+			}
+		}
+
+		if ( $dry_run || empty( $delete_keys ) ) {
+			return;
+		}
+
+		foreach ( array_chunk( array_values( $delete_keys ), 200 ) as $delete_chunk ) {
+			$where_parts = [];
+			$params      = [];
+			foreach ( $delete_chunk as $delete_item ) {
+				$where_parts[] = '(post_id = %d AND meta_key = %s)';
+				$params[]      = (int) $delete_item['post_id'];
+				$params[]      = (string) $delete_item['meta_key'];
+			}
+
+			$sql = "DELETE FROM {$wpdb->postmeta} WHERE " . implode( ' OR ', $where_parts );
+			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.NotPrepared
+			$wpdb->query( $wpdb->prepare( $sql, $params ) );
+		}
+
+		foreach ( array_chunk( $insert_rows, 500 ) as $insert_chunk ) {
+			$placeholders = [];
+			$params       = [];
+			foreach ( $insert_chunk as $insert_row ) {
+				$placeholders[] = '(%d, %s, %s)';
+				$params[]       = (int) $insert_row['post_id'];
+				$params[]       = (string) $insert_row['meta_key'];
+				$params[]       = (string) $insert_row['meta_value'];
+			}
+
+			if ( empty( $placeholders ) ) {
+				continue;
+			}
+
+			$sql = "INSERT INTO {$wpdb->postmeta} (post_id, meta_key, meta_value) VALUES " . implode( ', ', $placeholders );
+			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching,WordPress.DB.PreparedSQL.NotPrepared
+			$wpdb->query( $wpdb->prepare( $sql, $params ) );
+		}
+	}
+
+	/**
+	 * Append meta dry run log.
+	 *
+	 * @since 0.9.0
+	 * @param string $key Meta key.
+	 * @param string $value Meta value.
+	 * @param array  $dry_run_log Dry run log.
+	 * @return void
+	 */
+	private function append_meta_dry_run_log( string $key, string $value, array &$dry_run_log ): void {
+		$dry_run_log_limit = (int) apply_filters( 'fe_csv_import_export_dry_run_log_limit', 50 );
+		$values            = $this->get_csv_util()->split_pipe_separated_values( $value );
+		if ( count( $values ) > 1 ) {
+			foreach ( array_map( 'trim', $values ) as $single_value ) {
+				if ( '' === $single_value ) {
+					continue;
+				}
+				$dry_run_log[] = sprintf(
+					/* translators: 1: field name, 2: field value */
+					__( 'Custom field (multi-value): %1$s = %2$s', 'fe-csv-import-export' ),
+					$key,
+					$single_value
+				);
+				if ( count( $dry_run_log ) > $dry_run_log_limit ) {
+					$dry_run_log = array_slice( $dry_run_log, -1 * $dry_run_log_limit );
+				}
+			}
+			return;
+		}
+
+		$single_value  = trim( (string) ( $values[0] ?? '' ) );
+		$dry_run_log[] = sprintf(
+			/* translators: 1: field name, 2: field value */
+			__( 'Custom field: %1$s = %2$s', 'fe-csv-import-export' ),
+			$key,
+			$single_value
+		);
+		if ( count( $dry_run_log ) > $dry_run_log_limit ) {
+			$dry_run_log = array_slice( $dry_run_log, -1 * $dry_run_log_limit );
+		}
+	}
+
 	/**
 	 * Normalize header/field name.
 	 *
diff --git a/includes/import/class-fe-csv-import-export-import-wp-compatible.php b/includes/import/class-fe-csv-import-export-import-wp-compatible.php
index fd0ea35..fe668ae 100644
--- a/includes/import/class-fe-csv-import-export-import-wp-compatible.php
+++ b/includes/import/class-fe-csv-import-export-import-wp-compatible.php
@@ -152,6 +152,39 @@ public function import(): void {
 			$this->cleanup_import_session( $import_session );
 		}
 
+		$profile         = isset( $counters['import_profile'] ) && is_array( $counters['import_profile'] ) ? $counters['import_profile'] : [];
+		$profile_details = sprintf(
+			'start=%d size=%d processed=%d ensure=%.4fs read=%.4fs process=%.4fs total=%.4fs preload=%.4fs row_context=%.4fs row_processor=%.4fs success_log=%.4fs success_counter_guid=%.4fs prepare_meta_tax=%.4fs compat_hooks=%.4fs meta_apply=%.4fs tax_apply=%.4fs tax_resolve=%.4fs tax_set_terms=%.4fs tax_set_terms_calls=%d tax_set_terms_skipped=%d rows_profiled=%d memory_delta=%d peak=%d',
+			$start_row,
+			$batch_size,
+			(int) $counters['processed'],
+			$ensure_elapsed,
+			$read_elapsed,
+			$process_elapsed,
+			microtime( true ) - $batch_started_at,
+			(float) ( $profile['preload'] ?? 0.0 ),
+			(float) ( $profile['row_context'] ?? 0.0 ),
+			(float) ( $profile['row_processor'] ?? 0.0 ),
+			(float) ( $profile['success_log'] ?? 0.0 ),
+			(float) ( $profile['success_counter_guid'] ?? 0.0 ),
+			(float) ( $profile['prepare_meta_tax'] ?? 0.0 ),
+			(float) ( $profile['compat_hooks'] ?? 0.0 ),
+			(float) ( $profile['meta_apply'] ?? 0.0 ),
+			(float) ( $profile['tax_apply'] ?? 0.0 ),
+			(float) ( $profile['tax_resolve'] ?? 0.0 ),
+			(float) ( $profile['tax_set_terms'] ?? 0.0 ),
+			(int) ( $profile['tax_set_terms_calls'] ?? 0 ),
+			(int) ( $profile['tax_set_terms_skipped'] ?? 0 ),
+			(int) ( $profile['rows_profiled'] ?? 0 ),
+			memory_get_usage( true ) - $batch_memory_start,
+			memory_get_peak_usage( true )
+		);
+
+		if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
+			// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
+			error_log( '[FE CSV Import & Export] Batch profile: ' . $profile_details );
+		}
+
 		if ( $enable_logs && is_callable( $append_log ) ) {
 			$append_log(
 				[
@@ -159,18 +192,7 @@ public function import(): void {
 					'status'  => 'info',
 					'row'     => $start_row + 1,
 					'title'   => 'Batch profile',
-					'details' => sprintf(
-						'start=%d size=%d processed=%d ensure=%.4fs read=%.4fs process=%.4fs total=%.4fs memory_delta=%d peak=%d',
-						$start_row,
-						$batch_size,
-						(int) $counters['processed'],
-						$ensure_elapsed,
-						$read_elapsed,
-						$process_elapsed,
-						microtime( true ) - $batch_started_at,
-						memory_get_usage( true ) - $batch_memory_start,
-						memory_get_peak_usage( true )
-					),
+					'details' => $profile_details,
 				]
 			);
 		}
diff --git a/package.json b/package.json
index c31a288..4ab9861 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "fe-csv-import-export",
-	"version": "0.9.9.3",
+	"version": "1.0.0",
 	"description": "FE CSV Import & Export - Simple CSV Management Without the Complexity.",
 	"license": "GPL-2.0+",
 	"engines": {
diff --git a/readme.txt b/readme.txt
index 256cdce..555adfe 100644
--- a/readme.txt
+++ b/readme.txt
@@ -4,7 +4,7 @@ Tags: csv, import, export, custom post types, custom fields
 Requires at least: 6.6
 Tested up to: 7.0
 Requires PHP: 8.1
-Stable tag: 0.9.9.4
+Stable tag: 1.0.0
 License: GPLv2 or later
 License URI: https://www.gnu.org/licenses/gpl-2.0.html
 
@@ -135,6 +135,14 @@ No. The free version works on its own. A Pro version is available separately for
 
 == Changelog ==
 
+= 1.0.0 =
+
+* **Taxonomy optimization for unchanged terms** - Import now skips wp_set_post_terms() calls when taxonomy terms are unchanged, significantly reducing processing time for update-heavy imports.
+* **Increased default batch size** - Default import batch size increased from 100 to 500 rows, reducing AJAX overhead for large imports.
+* **Configurable batch size limit** - New fe_csv_import_export_import_max_batch_size filter allows per-site customization of the maximum batch size.
+* **Detailed import profiling** - Added granular profiling for import phases with WP_DEBUG batch profile logging.
+* **Fixed JavaScript ES module import syntax** - Removed static ES module imports from main JS file to resolve browser syntax errors.
+
 = 0.9.9.4 =
 
 * Bundled JavaScript files to reduce HTTP requests and improve page load performance.
diff --git a/test-release.sh b/test-release.sh
index 6a81546..1ff7841 100755
--- a/test-release.sh
+++ b/test-release.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 
 BRANCH="${1:-$(git rev-parse --abbrev-ref HEAD)}"
 RELEASE_DIR="test-release"
-ZIP_NAME="fe-csv-import-export-dev.zip"
+ZIP_NAME="fe-csv-import-export-1.0.0.zip"
 GENERATED_MINIFIED_FILES=(
 	"assets/css/fe-csv-import-export-style.min.css"
 	"assets/js/export/fe-csv-import-export/ajax.min.js"