It’s 2023, we are almost already at Passkeys and you skipped TOTP (basically that “Google Authenticator” does) as 2FA?
anyway there are a lot of open source TOTP apps available to choose from like Aegis or if you want to sync it something like Bitwarden (Premium or Vaultwarden)
desktop apps also exist but that would defeat the point probably
stay away from proprietary apps and do backups of these TOTP secrets or you’ll absolute will lock you out if you loose your phone somehow