Which two factor is the best? Google authenticator or just Authy?
Try to use better apps that need to be open-source.
Most of these are not open source and do not allow proper encrypted back ups. Google Authenticator in particular is awful from the regard. FreeOTP is no longer in development. Here are the apps you should be using:
Android -
Aegis or
AndOTPiOS -
Tofu or
Authenticator