I've used this for several years – Sophos Authenticator Review

Two factor authentication is a way to protect your account from hackers. Sites that use 2FA need both your password and the 6-digit code generated by your authentication app. This 6-digit code is generated every 30 seconds, thereby making it difficult for people to hack into your account. Most apps don't store codes on the cloud (a good thing), so the algorithm that creates the code is lost when you switch devices (an annoying thing). The solution is to use two devices to scan the same QR code. Sophos Authenticator is a universal app, and I have it on both my iPhone and iPad. When I set up my site for 2FA, I make sure I have both devices. Sophos has been around for decades, and I've never had an issue in using their authenticator app.
Review by irondog70 on Sophos Authenticator.