Oauth or in-built auth

I’ve just discovered @romanmg and CNCA’s Outlook plugin. I’m intrigued. Right now, I’m using bubble’s in-built auth, but I’m seriously thinking about switching to an oauth setup. But I’m not sure it would work, as the app is a paid app where accounts are added at onboarding (ie: an admin creates an account and sends creds). I’d love to use MS AAD to auth, but don’t know that fits my use case.

Anybody have any thoughts? Maybe I could do a “anybody can have an account, but to gain full functionality, you need to sign up” kind of deal.

Anybody have any advice?