Submitted title is misleading. Turns out, it's not "all but OAuth", it's "all but OAuth and app password".
If you can't switch to OAuth, you can simply create an app password and continue using that as your IMAP password as usual.
If you can't switch to OAuth, you can simply create an app password and continue using that as your IMAP password as usual.
Edit: that's incorrect, see replies.
-- Google, when you make an App Password