In our hosting, this is handled automatically. In self-hosted sites, it’s running into the issue you described. There is no event or screen in the admin UI where an admin indicates to the app that they are about to change the domain of the app, so we can’t act on it at the right time…
A similar issue happens with all the other social login providers, they need new apps to be created. Did you see any issues in the admin dashboard? I would expect problem checks to possibly have fired.