I had the new phone Google Authenticator lost data problem too. I use Authy now. It is attached to your email and phone number so you can login when you get a new phone
There was an update to the GA app a year or two back that screwed up the saved data and lost a lot of people access to their stuff... Google's answer was "Sorry, our bad. We'll have a new version of the app out that doesn't do this in a few weeks or whenever we get around to it, but all your lost stuff is gone. Soz..."
Protip: Don't allow your TFA app/hardware to be a single point of failure. Don't upgrade your reserve TFA device/apps until you're 100% sure the upgrade on your primary TFA device/app has worked smoothly.
Anyway, I have one time codes for all accounts I use 2FA with. Google generates these one time codes as TOTP substitutes, LastPass generates them as a one time master password that's TOTP exempt. Amazon you have to send an email and they'll call to verify and then unset 2FA on the account.
