A plugin that replaces WP Bakery's visual composer column shortcodes with native Gutenbeg blocks (use at you own discretion since inner content might not be parsed as expected)- You can user the Code Snippets plugin to run this code.

visual_composer_columns_to_wordpress_native_blocks.php

<?php

/*
Plugin Name: VC Columns to Native Blocks
Description: Convierte [vc_row][vc_column]...[/vc_column][/vc_row] en bloques nativos de columnas, párrafos e imágenes.
Author: Álvaro Gómez
Version: 1.4.0
*/

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class AG_VC_Columns_To_Native {

	protected $last_report = null;

	public function __construct() {
		add_action( 'admin_menu', array( $this, 'register_tools_page' ) );
	}

	public function register_tools_page() {
		add_management_page(
			'Convert VC Columns',
			'Convert VC Columns',
			'manage_options',
			'ag-vc-columns-to-native',
			array( $this, 'render_tools_page' )
		);
	}

	public function render_tools_page() {
		if ( ! current_user_can( 'manage_options' ) ) {
			return;
		}

		if ( isset( $_POST['ag_vc_convert_nonce'] ) && wp_verify_nonce( $_POST['ag_vc_convert_nonce'], 'ag_vc_convert' ) ) {
			$this->last_report = $this->run_conversion();
			$this->print_report_notice();
		}

		echo '<div class="wrap">';
		echo '<h1>Convert VC Columns to Native Blocks</h1>';
		echo '<p>Este script buscará patrones [vc_row][vc_column]...[/vc_column][/vc_row] en el contenido y los convertirá a bloques nativos de columnas, párrafos e imágenes.</p>';

		echo '<form method="post">';
		wp_nonce_field( 'ag_vc_convert', 'ag_vc_convert_nonce' );
		submit_button( 'Run conversion' );
		echo '</form>';

		if ( $this->last_report ) {
			$this->print_detailed_report_table();
		}

		echo '</div>';
	}

	protected function print_report_notice() {
		if ( ! $this->last_report ) {
			return;
		}

		$r = $this->last_report;

		echo '<div class="notice notice-success is-dismissible">';
		echo '<p><strong>Conversion finished.</strong></p>';
		echo '<p>';
		echo 'Posts scanned: ' . intval( $r['scanned'] ) . '<br>';
		echo 'Posts updated: ' . intval( $r['updated'] ) . '<br>';
		echo 'VC row groups converted: ' . intval( $r['groups_converted'] ) . '<br>';
		echo 'VC rows skipped (unparsed): ' . intval( $r['rows_skipped'] );
		echo '</p>';

		if ( ! empty( $r['updated_ids'] ) ) {
			echo '<p>Updated post IDs: ' . esc_html( implode( ', ', $r['updated_ids'] ) ) . '</p>';
		}

		echo '</div>';
	}

	protected function print_detailed_report_table() {
		$r = $this->last_report;

		if ( empty( $r['details'] ) ) {
			return;
		}

		echo '<h2>Details</h2>';
		echo '<table class="widefat striped">';
		echo '<thead><tr>';
		echo '<th>Post ID</th>';
		echo '<th>Title</th>';
		echo '<th>Rows found</th>';
		echo '<th>Rows converted</th>';
		echo '<th>Rows skipped</th>';
		echo '</tr></thead>';
		echo '<tbody>';

		foreach ( $r['details'] as $post_id => $info ) {
			printf(
				'<tr><td>%d</td><td>%s</td><td>%d</td><td>%d</td><td>%d</td></tr>',
				$post_id,
				esc_html( get_the_title( $post_id ) ),
				intval( $info['rows_found'] ),
				intval( $info['rows_converted'] ),
				intval( $info['rows_skipped'] )
			);
		}

		echo '</tbody>';
		echo '</table>';
	}

	protected function run_conversion() {
		global $wpdb;

		$post_ids = $wpdb->get_col(
			"SELECT ID FROM {$wpdb->posts}
			 WHERE post_type IN ('post','page')
			   AND post_status IN ('publish','draft','pending','future','private')
			   AND post_content LIKE '%[vc_row%'"
		);

		$report = array(
			'scanned'          => 0,
			'updated'          => 0,
			'groups_converted' => 0,
			'rows_skipped'     => 0,
			'updated_ids'      => array(),
			'details'          => array(),
		);

		if ( empty( $post_ids ) ) {
			return $report;
		}

		foreach ( $post_ids as $post_id ) {
			$report['scanned']++;

			$content         = get_post_field( 'post_content', $post_id );
			$original        = $content;
			$rows_found      = 0;
			$rows_converted  = 0;
			$rows_skipped    = 0;

			// Match each complete vc_row block.
			$pattern = '/\[vc_row\b(.*?)\](.*?)\[\/vc_row\]/is';
			if ( preg_match_all( $pattern, $content, $matches, PREG_SET_ORDER ) ) {
				$rows_found = count( $matches );

				foreach ( $matches as $match ) {
					$full_match   = $match[0];
					$row_inner    = $match[2];

					$converted = $this->convert_row_to_columns_block( $row_inner );

					if ( $converted === null ) {
						$rows_skipped++;
						continue;
					}

					$rows_converted++;
					$content = str_replace( $full_match, $converted, $content );
				}
			}

			if ( $content !== $original ) {
				$updated_post = array(
					'ID'           => $post_id,
					'post_content' => $content,
				);

				$result = wp_update_post( $updated_post, true );

				if ( ! is_wp_error( $result ) ) {
					$report['updated']++;
					$report['groups_converted'] += $rows_converted;
					$report['rows_skipped']     += $rows_skipped;
					$report['updated_ids'][]     = $post_id;

					$report['details'][ $post_id ] = array(
						'rows_found'     => $rows_found,
						'rows_converted' => $rows_converted,
						'rows_skipped'   => $rows_skipped,
					);
				}
			}
		}

		return $report;
	}

	/**
	 * Convierte el contenido interno de un [vc_row] en un bloque <!-- wp:columns -->...
	 * Devuelve null si no puede parsear columnas.
	 */
	protected function convert_row_to_columns_block( $row_inner ) {
		// Capturar todas las columnas de primer nivel dentro del row.
		$pattern = '/\[vc_column\b([^]]*)\](.*?)\[\/vc_column\]/is';
		if ( ! preg_match_all( $pattern, $row_inner, $cols, PREG_SET_ORDER ) ) {
			return null;
		}

		$columns_html = array();

		foreach ( $cols as $col_match ) {
			$col_attrs  = $col_match[1];
			$col_inner  = $col_match[2];

			// 1) Convertir [vc_column_text] a párrafos (dentro, <img> a bloques image).
			$col_inner = $this->convert_vc_column_text_to_paragraph( $col_inner );

			// 2) Convertir <img> sueltos en la columna en bloques image (caso como el que comentas).
			$col_inner = $this->convert_imgs_to_image_blocks( $col_inner );

			$columns_html[] =
				"<!-- wp:column -->\n" .
				'<div class="wp-block-column">' . $col_inner . "</div>\n" .
				"<!-- /wp:column -->";
		}

		if ( empty( $columns_html ) ) {
			return null;
		}

		$columns_block =
			"<!-- wp:columns -->\n" .
			'<div class="wp-block-columns">' . "\n\n" .
			implode( "\n\n", $columns_html ) . "\n\n" .
			"</div>\n" .
			"<!-- /wp:columns -->";

		return $columns_block;
	}

	/**
	 * Reemplaza [vc_column_text]$content[/vc_column_text] por
	 * <!-- wp:paragraph -->$content<!-- /wp:paragraph --> preservando $content,
	 * y dentro de ese contenido convierte <img> en bloques de imagen.
	 */
	protected function convert_vc_column_text_to_paragraph( $content ) {
		$pattern = '/\[vc_column_text\b[^\]]*\](.*?)\[\/vc_column_text\]/is';

		$callback = function ( $m ) {
			$inner = $m[1];

			// Primero, convertir cualquier <img ...> dentro de $inner a bloques de imagen.
			$inner = $this->convert_imgs_to_image_blocks( $inner );

			return "<!-- wp:paragraph -->" . $inner . "<!-- /wp:paragraph -->";
		};

		return preg_replace_callback( $pattern, $callback, $content );
	}

	/**
	 * Convierte <img> en bloques de imagen:
	 *
	 * <img src="..." class="... wp-image-8 ..." ...>
	 *
	 * pasa a:
	 *
	 * <!-- wp:image {"id":8,"sizeSlug":"large","linkDestination":"none"} -->
	 * <figure class="wp-block-image size-large"><img src="..." alt="" class="wp-image-8"/></figure>
	 * <!-- /wp:image -->
	 *
	 * El ID se toma del número en la clase wp-image-N.
	 */
	protected function convert_imgs_to_image_blocks( $html ) {
		$pattern = '/<img\b([^>]*)>/i';

		$callback = function ( $m ) {
			$attrs_str = $m[1];

			// Extraer src.
			$src = '';
			if ( preg_match( '/\bsrc\s*=\s*"([^"]*)"/i', $attrs_str, $m_src ) ) {
				$src = $m_src[1];
			}

			// Extraer clase completa (para conservar wp-image-N).
			$class_attr = '';
			if ( preg_match( '/\bclass\s*=\s*"([^"]*)"/i', $attrs_str, $m_class ) ) {
				$class_attr = $m_class[1];
			}

			// Extraer ID de wp-image-N.
			$id = 0;
			if ( preg_match( '/wp-image-([0-9]+)/', $class_attr, $m_id ) ) {
				$id = (int) $m_id[1];
			}

			if ( empty( $src ) || $id <= 0 ) {
				// Si no tenemos src o id válido, no tocamos el <img>.
				return $m[0];
			}

			// Asegurar que la clase wp-image-N está presente (y sólo una vez).
			$classes = preg_split( '/\s+/', trim( $class_attr ) );
			if ( ! in_array( 'wp-image-' . $id, $classes, true ) ) {
				$classes[] = 'wp-image-' . $id;
			}
			$classes = array_filter( $classes );
			$class_final = implode( ' ', $classes );

			// Construir atributos del comentario del bloque.
			$comment_attrs = sprintf(
				'{"id":%d,"sizeSlug":"large","linkDestination":"none"}',
				$id
			);

			// Figure estándar de bloque de imagen.
			$img_tag = sprintf(
				'<figure class="wp-block-image size-large"><img src="%1$s" alt="" class="%2$s"/></figure>',
				esc_url( $src ),
				esc_attr( $class_final )
			);

			$block  = '<!-- wp:image ' . $comment_attrs . ' -->' . "\n";
			$block .= $img_tag . "\n";
			$block .= '<!-- /wp:image -->';

			return $block;
		};

		return preg_replace_callback( $pattern, $callback, $html );
	}

}

new AG_VC_Columns_To_Native();