I worked around this problem by adding an entry in my password manager with a username of "OAuth: Use Google" or something like that, so I'm informed when I habitually check my browser extension or when I attempt to auto-fill during login.
It's inelegant and could be better, but good enough.
If you use a password manager (and my condolences to those who don't), there's really no benefit to using OAuth over an email sign up. It can prepopulate your personal information, but I usually don't want that for the services I sign up for.
There's a couple of services where I prefer to use github for sso because I need them to integrate with data stored there, and it makes sense to me to "bundle" those accounts. But that's very much an edge case.
Is this where I complain about companies that insist I install their MFA app rather than just letting me use Google Authenticator? You're not special.
It's inelegant and could be better, but good enough.