Does the Apple App Store review process require a demo account for signing in via a "Sign in with Apple" button? For example, if that is the only sign-in method, how would one create a demo account?
The App Store Review Guidelines state to "include demo account info [...] if your app includes a login."
Apple can use their accounts for Apple sign in.
If you didn’t rely exclusively on Apple for app identity, you would want to provide an account of your issuance so you can see what the testers hit. Not giving them an account makes you miss getting feedback. (imo)
As you stated, you can’t issue an AppleID to testers, they must do that themselves.
