Hello,
We’ve checked more deeply, Related products are displayed in our theme randomly, by default. But on your site it is not, so check if you did any changes in files that may affect it, for example changes in xstore-child/woocommerce/single-product/related.php, or maybe something from 3rd party plugins affects related products.
You can try to add the next code in functions.php of the child theme:
add_filter('woocommerce_related_products_args', function($args) {
$args['orderby'] = 'rand';
return $args;
}, 9999);
If you need any further assistance with this, provide temporary wp-admin and FTP access, so we can take a closer look.
Regards