Failing that, you can upgrade your app to pro and if that is working, then downgrade the other one. You will not be charged twice. They put a credit on your account when you downgrade from pro.
In addition, once you have the backup working as pro, you can set up the URL so it points to the backup which you’ve just upgraded to pro.
The key is to do everything a step at a time and test after each step to make sure it’s doing what you want.