We checked your site and found following. You changed content single product file and removed using of the single product builder code for your products, so it means that single builder settings does not work for you and we have disabled single product builder editor. Related products of the built-in layout does not have option to disable out of stock products for the related products section. Anyway, we have made additional customization in your child theme to hide out of stock products from the related products even with the built-in layout.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.