When using the relationship ACF field, this snippet will only show the published items of the specified CPT.

In this example, the CPT is ‘Services’ and ‘services_list’ is the name of the ACF Relationship field.
$options uses the WP_Query arguments used to specify the post status we want.

function cpt_services_relationship_filter( $options ) {
	$options['post_status'] = array( 'publish' );
	return $options;
}
add_filter( 'acf/fields/relationship/query/name=services_list', 'cpt_services_relationship_filter' );

Additional Reading:

• ACF Docs: Relationship
• ACF Docs: Relationship Query