Force ACF fields loaded over JSON fiels to be translated though gettext

wp-acf-force-json-load-translation.php

<?php

/**
 * Force ACF fields loaded over JSON fiels to be translated though gettext
 */
add_filter( 'acf/load_field',

	/**
	 * Force ACF to try to translate fields even when they come from JSON.
	 *
	 * @param array $field
	 *
	 * @return array
	 */
	function ( array $field ): array {
		$field['label']         = __( $field['label'] ?? '', 'custom-domain' );
		$field['instructions']  = __( $field['instructions'] ?? '', 'custom-domain' );
		$field['default_value'] = __( $field['default_value'] ?? '', 'custom-domain' );
		$field['placeholder']   = __( $field['placeholder'] ?? '', 'custom-domain' );
		$field['prepend']       = __( $field['prepend'] ?? '', 'custom-domain' );
		$field['append']        = __( $field['append'] ?? '', 'custom-domain' );

		return $field;
	}
);

add_filter( 'acf/load_field_group',

	/**
	 * Force ACF to try to translate groups even when they come from JSON.
	 *
	 * @param array $group
	 *
	 * @return array
	 */
	function ( array $group ): array {
		$group['title']       = __( $group['title'], 'custom-domain' );
		$group['description'] = __( $group['description'], 'custom-domain' );

		return $group;
	}
);