Though the app is not in the OS directly so each email account used in Dekko 2 would need password plus another verification for Google to except it, if I have that right of course.
Can't say if you're right, because I don't actually have a gmail account myself. I haven't been aware of big G enforcing 2FA now. Though, I've seen gmail support pages explaining how to turn off "2-step-verification".
What triggered my response was the fact that I've seen old, EOS phones having to be finally retired when mail providers tightened their list of accepted ciphers. 20.04 based UT will certainly stretch the live span of some phones (if not for gmail users).