Hacker News Reader

Not linked to your phone number. It does encrypted backup that can be synced with Google Android backup (if you want).

Support Steam authenticator (if you follow the guide how to get the key).

You can group the MFA provider in groups that make sense to you.

You're in full control and the keys never leave your device unless you want to.

You can see the keys whenever you decide.

And the list goes on. I've been using it for years and it's the best MFA app on the market.

Authy has no official backup-solution, it's vendor lockin. They discontinued their desktop-app last week, are owned by a company, and so you never know when they might charge money or discontinue the app as a whole.

There are unofficial solutions for backup, but who knows when those will stop working.

FOSS, import/export.