[Frontend Snippets] Custom sorting options (asc/desc)

wc-custom-sorting-options-asc-dec.php

/**
 * Add custom sorting options (asc/desc)
 */
add_filter( 'woocommerce_get_catalog_ordering_args', 'custom_woocommerce_get_catalog_ordering_args' );
function custom_woocommerce_get_catalog_ordering_args( $args ) {
  $orderby_value = isset( $_GET['orderby'] ) ? wc_clean( $_GET['orderby'] ) : apply_filters( 'woocommerce_default_catalog_orderby', get_option( 'woocommerce_default_catalog_orderby' ) );
	if ( 'random_list' == $orderby_value ) {
		$args['orderby'] = 'rand';
		$args['order'] = '';
		$args['meta_key'] = '';
	}
	return $args;
}
add_filter( 'woocommerce_default_catalog_orderby_options', 'custom_woocommerce_catalog_orderby' );
add_filter( 'woocommerce_catalog_orderby', 'custom_woocommerce_catalog_orderby' );
function custom_woocommerce_catalog_orderby( $sortby ) {
	$sortby['random_list'] = 'Random';
	return $sortby;
}

I would like to sort products based on a custom attribute.
I started with this random sorting script, but not being a programmer I haven't been able to get it to work yet.
The latest proof is this:

`
/**
Add custom sorting options (asc/desc)
*/

add_filter( 'woocommerce_get_catalog_ordering_args', 'custom_woocommerce_get_catalog_ordering_args' );
function custom_woocommerce_get_catalog_ordering_args( $args ) {
$orderby_value = isset( $_GET['orderby'] ) ? wc_clean( $_GET['orderby'] ) : apply_filters( 'woocommerce_default_catalog_orderby', get_option( 'woocommerce_default_catalog_orderby' ) );
if ( 'product_attribute_taxonomies' == $orderby_value ) {
$args['orderby'] = 'meta_value_num';
$args['order'] = 'ASC';
$args['meta_key'] = 'pa_kj';
}
return $args;
}
add_filter( 'woocommerce_default_catalog_orderby_options', 'custom_woocommerce_catalog_orderby' );
add_filter( 'woocommerce_catalog_orderby', 'custom_woocommerce_catalog_orderby' );
function custom_woocommerce_catalog_orderby( $sortby ) {
$sortby['product_attribute_taxonomies'] = 'Order by Kj';
return $sortby;
}

`
but it does not work: "No products were found matching your selection."

My attribute name is "pa_kj" Its value is alphanumeric

I thank everyone in advance for any suggestions.