AuthGeek
Free offline two factor authenticator for Windows - no account
...Add accounts however you have them: paste the setup link, read the QR code out of a screenshot, or type the secret in by hand. TOTP and HOTP are both supported, and you can bring the whole lot across from Google Authenticator.
Backup is an encrypted file with a password of its own, or a plain text export if you know what you are doing. Restore never replaces what is already there.
Free to use, including at work. Open source under GPL-3.0, no adverts, no telemetry. Windows 10 or 11, 64 bit.