Tip: The iPhone Passwords App has basic TOTP functionality (manually create a password entry and click “Set Up Code”). I have a few dummy passwords which are effectively just labels for some login codes - it’s one less App to install.
Some Microsoft setups ONLY allow Authenticator - can’t use 1pass etc. I have recently fallen into this pit
Unfortunately Microsoft Authenticator does more than TOTP and usually its not up to the user to decide which two factor implementation is accepted.