How do I select parent or child when using terms query loop?

21

I’m having a hard time making it work via the backend settings, can anyone help me?

I have an archive template for custom taxonomy term.

For the current selected term i want to display it’s child terms.

I can achieve this via php:

add_filter( 'bricks/terms/query_vars', 'gbe_query_vars_terms_filter', 12, 3 );

function gbe_query_vars_terms_filter( $query_vars, $settings, $element_id ) {
	if( $element_id == 'fac21f' ) {
		$parentID = get_queried_object()->term_id;
		$children = get_terms( 'servizio', array( 'parent' => $parentID, 'orderby' => 'slug', 'hide_empty' => false ) );

		$query_vars['exclude'] = [ $parentID ];
		$query_vars['include'] = array();

		foreach ( $children as $child )
		{
			$query_vars['include'][] = $child->term_id;
			echo $child->term_id;
		}
	}

	return $query_vars;
}

Can I make this work using the back-end settings only?