Google 2FA work offilne with local data. You loss phone or fail device, you loss. Use Titanium backup to avoid data loss
when i restored a backup of my old dead note 4 to my replacement note 4, google auth didnt transfer although everything else did. i had to re input the google auth codes from paper backups.
it wasnt titanium backup though, i used samsungs backup software. i assume titanium needs a rooted phone? (mine isnt rooted).