I wholeheartedly dislike GMail (ethically, technically, and UX), and for my personal email I have always run my own server. But for work email I don’t have a choice. I am using isync/mbsync to make it usable for me and mutt. Until now I’ve used a Google app password to authenticate, but they are a security nightmare. OAuth2 is a better way. Sadly the interwebs have only scarce, outdated, or buggy recipes, so I finally spent the better part of an afternoon and moved OAuth2.