Ooh, I've never looked into it, but I would have thought that with this feature the website explicitly does NOT get my email address. Silly me, still believing some features are meant for the user.
https://superuser.com/questions/1414410/how-to-disable-googl...
I can't confirm whether the email is still shared. It used to be the case from late 2010s up to a few years ago.
It would be easy to assume that other oath providers are doing the same but absolutely not.
This is quite visible in User Accounts where I work... while they do cause some issues from time to time (when the user disables the relay address for an active account), it guarantees privacy.
But I don't know if other popular single-sign-on provider do this.