How to sort products by rating or first those with a promotion?

Question

WordPress

Hello!
Please tell me how to sort products in categories by rating or display first those that have a discount?
So I found a function, it displays only by price, that is, first those with the highest price ...

add_filter('woocommerce_get_catalog_ordering_args', 'my_woocommerce_order');
function my_woocommerce_order($args){
        $args['orderby']  = 'meta_value_num';
        $args['order']    = 'DESC';
        $args['meta_key'] = '_price'; 
 return $args;
}