[omarhaneef]

Microsoft Authenticator syncs across all instances so you just have to log in to a new Authenticator on the new phone and the codes are there. (I think it uses OneDrive).

I am sure that is less secure than a local only copy but this may be least bad of all alternatives.

You might even give a trusted person a login and have it on their phone so you can use theirs in an emergency.

[Nextgrid]

How do you login to the authenticator itself? If it's MS-account-based doesn't that itself requires 2FA and you thus have a chicken & egg problem?

[ranger_danger]

It doesn't need a login... only the syncing part uses your account.