Earlier quoted context omitted.
(I'm not the person to whom you were replying) One of my "important things" is a 32-bit app required for a freelance project. This freelance project also requires some 64-bit apps, so I don't see how two partitions would help here. Am I missing something? (Sincere question -- I'm looking for a new solution because I know Mojave won't be supported forever.)
If that 32-bit app has a Windows version, you could run it on current macOS using CrossOver. Performance might take a hit depending on what you're doing, but the MacBook Pro M1 runs Windows games fairly well in CrossOver. Wine might also work. If the app only available for 32-bit macOS, I suppose your remaining options are running Mojave in a local VM, or in the cloud (AWS offers Mojave instances for example) for you…
Thank you for the suggestions :)