Mail account authentication with Oauth2
UPDATE: It's available now for INBOUND emails (bounce processing/email processor) in 5.32 as a hidden extension. See https://docs.civicrm.org/sysadmin/en/latest/setup/oauth/#enable-the-module

It's in progress for google and would likely be the same for outlook/exchange.
See https://lab.civicrm.org/dev/mail/issues/59
It supports using a bearer token already
but we could use some coding help though for someone to write the code to get/store/use the refresh tokens in order to get the bearer token.