show related product by primary category in wordpress

I have products with two categories assigned I selected the primary category on each products under category selection. Now I want to show related products by primary products.

I am using the yoast seo plugin.

I added the below filter code in the child theme's function.php file, but it's not working.

// Alter related products query to pull items from Yoast Primary Category
add_filter( 'woocommerce_get_related_product_cat_terms', function( $terms, $product_id ) {
    if ( function_exists( 'yoast_get_primary_term_id' ) ) {
        $primary_term_product_id = yoast_get_primary_term_id( 'product_cat', $product_id );
        if ( $primary_term_product_id ) {
            return array( $primary_term_product_id );
        }
    }
    return $terms;
}, 10, 2 );

The filter should be okay, problem is that related products in Wordpress are cached in database using transients.
The transients can be found in wp_options table with names _transient_wc_related_[product_id] and _transient_timeout_wc_related_[product_id].
In order to see the filter effect immediately you need to delete these from your database.

Following SQL query should do the deletion:

DELETE FROM wp_options WHERE option_name REGEXP '^_transient_timeout_wc_related_[0-9]*$|^_transient_wc_related_[0-9]*$'

After the deletion, wordpress will recreate new transients with updated data.
More info about Wordpress transients:
https://developer.wordpress.org/apis/handbook/transients/