AWS is crap in this regard, because you can only have a single 2FA device registered for your root account.

That means if you lose that 2FA device, you're hosed. Unless you can convince support to turn off your account's 2FA which one would hope they wouldn't do under any circumstances.

Instead, you should use TOTP with a mobile app. That way you can make a backup by enrolling several phones with the same QR code - or printing out the QR code and storing it somewhere safe.