/**
  * ElasticSearch: Modify available search fields
  */
  add_filter( 'ep_search_fields', function($search_fields, $args ) {
    $fields = ['my_field'];
    foreach($acf_fields as $key => $label) {
    $fields[] = 'meta.'.$key.'.value';
  }
  return array_merge( $search_fields, $fields );
 }, 10,2 );