Copy WP-Stateless field (`sm_cloud`) to all WPML translations on a media post upload to GCS.

wp-stateless-copy_to_all_translations.php

<?php

/**
 * Copy WP-Stateless field (`sm_cloud`) to all WPML translations on a media post upload to GCS.
 */
add_filter("wp_stateless_media_synced", function($metadata, $attachment_id, $force, $args) {

	global $sitepress;
	$trid = $sitepress->get_element_trid($attachment_id);
	$translations = $sitepress->get_element_translations($trid);

	// Get WP-Stateless field
	$cloud_meta = get_post_meta($attachment_id, "sm_cloud", true);

	if ($cloud_meta) {
		foreach ($translations as &$translation) {
			$this_translation_post_id = $translation->element_id;

			// Set field in other translations that are not the current one
			if ($this_translation_post_id != $attachment_id) {
				update_post_meta($this_translation_post_id, "sm_cloud", $cloud_meta);
			}
		}
	}

	return $metadata;
}, 10, 4);

I've got very little knowledge of PHP and WordPress, so please be aware when using this in production environments.
Happy to hear if this can be improved.