+1 for this, Just setting up authentik and was shocked to find HA cannot to Oauth2 etc. Quite bizarre for a platform that’s vision is a single integrated platform across multiple provider platforms - that’s exactly what SSO is from a login perspective.
To all those saying that it moves away from the “everything as local as possible” I have no idea why Oauth2 cannot be local (mine is) and who says that is everyone’s goal? For some yes, but for others not so much. HA is just as valid linking cloud platforms from disparate providers together.