If you want to federated eg AAD with Gsuite, it'll be via SAML, but I don't know of any consumer service that's ever supported SAML. It's so weird the author used Twitter when they were one of the classic original Oauth creators.
My thoughts exactly! A lot of the "social" things are OAuth based, not SAML. I know Google has both, but when doing consumerish things via Google, that's also OAuth based (iirc).