Same here.
The native mail and calendar app with Exchange support worked flawless, until I was forced to use 2FA. I could register my Phone with the SailOTP app for generating Tokens, but the mail app doesn’t support Modern Authentication. I raised a case with Jolla and they say that they will look into this feature request but have no planning or date when this will be implemented. They suggested that I should make a new feature request on the forum and with substantial likes, it might speed them up.
There is already a feature request for this by tehhel , however it’s hardly noticed.
https://forum.sailfishos.org/t/basic-authentication-deprecated-by-microsoft/2905?u=sakul
So I’m on the same page, locked out from my mail and calendar on my sailfish phone