If you have multiple relationship fields and want to target them all just add this to your functions.php.
add_filter( 'acf/fields/relationship/query','relationship_options_filter', 10, 3);
function relationship_options_filter($options, $field, $the_post) {
$options['post_status'] = array('publish');
return $options;
}
ref: https://www.advancedcustomfields.com/resources/acf-fields-post_object-query/