So basically what title says.
Im using 2FA with google authenticator for multiple accounts. What if my phone gets stolen? Can I have some kind of backup? Or maybe sync with some self hosted service?
Bonus question: what 2FA should I use instead of google?
All you need is the TOTP secret, and it will generate OTPs. If you enter the secret in another TOTP app, you’ll also get OTPs. Here’s a Ruby lib that will render OTPs from a secret, for example: https://github.com/mdp/rotp
For an Android TOTP tool, I like FreeOTP+. You can even use it for Steam OTPs.