@girish So clever! Worked like a charm.
The only part where I had to fuss for a few minutes is that the app errored on changing to the new domain; it got stuck on de-registering the old domain. I went into the Domain manager and deleted the domain entirely from the Cloudron and then the app was able to receive the new domain without problem.
Thank you so much for writing the steps out in detail. I really appreciate it!