Try alternative approach

packages/block-library/src/gallery/index.php

@@ -5,6 +5,35 @@
  * @package WordPress
  */
 
+/**
+ * Handles backwards compatibility for Gallery Blocks,
+ * whose images feature a `data-id` attribute.
+ *
+ * Now that the Gallery Block contains inner Image Blocks,
+ * we add a custom `data-id` attribute before rendering the gallery
+ * so that the Image Block can pick it up in its render_callback.
+ *
+ * @since 5.9.0
+ *
+ * @param array $parsed_block The block being rendered.
+ * @return array The migrated block object.
+ */
+function block_core_gallery_data_id_backcompatibility( $parsed_block ) {
+	if ( 'core/gallery' === $parsed_block['blockName'] ) {
+		foreach ( $parsed_block['innerBlocks'] as $key => $inner_block ) {
+			if ( 'core/image' === $inner_block['blockName'] ) {
+				if ( ! isset( $parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] ) && isset( $inner_block['attrs']['id'] ) ) {
+					$parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] = esc_attr( $inner_block['attrs']['id'] );
+				}
+			}
+		}
+	}
+
+	return $parsed_block;
+}
+
+add_filter( 'render_block_data', 'block_core_gallery_data_id_backcompatibility' );
+
 /**
  * Renders the `core/gallery` block on the server.
  *

packages/block-library/src/image/index.php

@@ -28,32 +28,34 @@ function render_block_core_image( $attributes, $content, $block ) {
 		return '';
 	}
 
-	if ( isset( $attributes['id'] ) ) {
-		$id = $attributes['id'];
-
-		// Use block context to detect whether the block is nested in a gallery.
-		// As the context names are very generic, check multiple array keys to
-		// reduce the chance a non-gallery parent is providing the same context.
-		$is_gallery_child = array_key_exists( 'allowResize', $block->context )
-			&& array_key_exists( 'imageCrop', $block->context )
-			&& array_key_exists( 'fixedHeight', $block->context );
-
-		// Adds the data-id="$id" attribute to the img element to provide backwards
-		// compatibility for the Gallery Block, which now wraps Image Blocks within
-		// innerBlocks. The data-id attribute is added in a core/gallery
-		// `render_block_data` hook.
-		if ( $is_gallery_child ) {
-			$p->set_attribute( 'data-id', $id );
-		}
+	/*
+	 * The data-id attribute is added in a core/gallery
+	 * `render_block_data` hook.
+	 */
+	if ( isset( $attributes['data-id'] ) ) {
+		// The initial id when the block was parsed.
+		$initial_id = $attributes['data-id'];
+		/*
+		 * The id attribute could change during rendering while applying block bindings.
+		 * If data-id attribute exists, it is safe to assume that
+		 * id attribute is also present.
+		 */
+		$rendered_id = $attributes['id'];
+		/*
+		 * Adds the data-id="$id" attribute to the img element to provide backwards
+		 * compatibility for the Gallery Block, which now wraps Image Blocks within
+		 * innerBlocks.
+		 */
+		$p->set_attribute( 'data-id', $rendered_id );
 
-		// If there's a mismatch with the 'wp-image-' class and the actual id, the id was
-		// probably overridden by block bindings. Update it to the correct value.
-		// See https://github.com/WordPress/gutenberg/issues/62886 for why this is needed.
-		$image_classnames  = $p->get_attribute( 'class' );
-		$expected_id_class = "wp-image-$id";
-		if ( is_string( $image_classnames ) && ! str_contains( $image_classnames, $expected_id_class ) ) {
-			$image_classnames = preg_replace( '/wp-image-(\d+)/', "wp-image-$id", $image_classnames );
-			$p->set_attribute( 'class', $image_classnames );
+		/*
+		 * If the id has changed, it was probably overridden by block bindings.
+		 * Update it to the correct value.
+		 * See https://github.com/WordPress/gutenberg/issues/62886 for why this is needed.
+		 */
+		if ( $initial_id !== $rendered_id ) {
+			$p->remove_class( 'wp-image-' . $attributes['data-id'] );
+			$p->add_class( 'wp-image-' . $rendered_id );
 		}
 	}