Agreed, I have an extra phone for gmail authenticator backup, also make sure to secure a pin code, you can use a paper or something and store in properly.
I really do not know why I prefer Authy to Gmail authenticator, which is by the way though. Backing up is not a problem if you can at least remember the email you used while setting up the authenticators be it, Authy or Gmail Authenticator.
For Authy however, it even helps with back up passwords which you can easily use to log in on any device after downloading the app and be able to have access back to all your linked 2FA logins so I have never found losing my device to be a problem.