It has been a few weeks since we started this, which European email provider have you switched to?

I use Aegis, an open source alternative that works just like Google and Microsoft Authenticator.

IDK what Google Authenticator does, but I just use KeepassXC's TOTP feature for my 2FA.

I use 2FAs. It's open-source but it seems to be based in Nevada.. Otherwise great app.

Proton pass has this functionality. You can also give it a separate password so if someone gets access to your proton email they can't get into pass

You can use any OTP App or device of your choosing. TOTP is a simple standard for 2FA which is why nobody necessarily needs Google or Microsoft Authenticator.

There is Aegis, FreeOTP, OTPManager (iOS/macOS) and many others. Some Password Managers like 1Password, BitWarden and KeepassXC also support OTP.