I think you are correct, I took a shortcut there ; my question is more "I used email A to sign in, and used my android creds (incidentally my fingerprint) - which is using my Gmail account B. Now I want to use my apple creds C to signin on my Mac.

What links are created between all these accounts? Does Google now know that their account B is linked to email A? Does Hankio? Or is that the service provider?