After 20 years of using bt email they now decree that I am too stupid to use a password only login and have to do 2 factor authentication. And their brilliant programmers cannot produce a login procedure that works in the Firefox web browser on a Mac. It does however work in the Edge browser in Windows 10. At least, the email login worked, but the bt account login failed when I tested yesterday.
I'm giving up with bt, they are hopeless.
No idea where you get notion that 2FA is compulsory on BT email. It isn't.
Maybe it's Apple paranoia.
So is your post just a moan or are you looking for some assistance?