I'll save you from my diatribe about the pitfalls of you-as-a-user of using Google or Microsoft for login. But because of that, I don't know and so can only gue

I'll save you from my diatribe about the pitfalls of you-as-a-user of using Google or Microsoft for login. But because of that, I don't know and so can only guess at what level OpenAI choses to rely on Google/Microsoft to validate accounts.