Didn’t read this but I ditched authy a year ago (close call!)

I recommend using Aegis (you can export and import everything all at once)

You can then use syncthing to keep your phone and other devices in sync.

Even if you don’t mind your phone number getting leaked because it’s already out there I would recommend to switch away from a closed source software that requires your phone number for no good reason. Even if it’s just to send a signal that this is not ok.