How can I custom order the product display?

You can use woocommerce_shortcode_products_query filter to change orderby argument. it will set orderby as post__in in [products] shortcode query. I have tested and it is working fine for me. you can take reference from below code and adjust code as per your need. Let me know if this works for you!

add_filter( 'woocommerce_shortcode_products_query', 'woocommerce_shortcode_products_orderby_post_in' );
function woocommerce_shortcode_products_orderby_post_in( $args ) {
    if( isset( $args['orderby'] ) ) {
        $args['orderby']  = 'post__in'; 
    }
    return $args;
}