I was curious to see if FairEmail could work with OAuth without Google Play (I have a school Google account that does not allow me to log in without OAuth):

https://github.com/M66B/FairEmail/blob/master/FAQ.md#user-co...

"OAuth for Gmail is supported via the quick setup wizard. The Android account manager will be used to fetch and refresh OAuth tokens for selected on-device accounts. OAuth for non on-device accounts is not supported because Google requires a yearly security audit ($15,000 to $75,000) for this. You can read more about this here."

You can see it here too: https://support.google.com/cloud/answer/9110914#zippy=%2Cexc...