As confirmed in the comments by @Thilo if app provides non third party login option then app will be approved, this rule is applicable only for the apps which is having exclusive third-party option.
As per the AppStore review guidelines, now apps which are offering sign in with other social services also need the option of apple sign in.
4.8 Sign in with Apple Apps that exclusively use a third-party or social login service (such as Facebook Login, Google Sign-In, Sign in with Twitter, Sign In with LinkedIn, Login with Amazon, or WeChat Login) to set up or authenticate the user’s primary account with the app must also offer Sign in with Apple as an equivalent option. A user’s primary account is the account they establish with your app for the purposes of identifying themselves, signing in, and accessing your features and associated services.
We are planning to upload a new app with social sign-in options today which doesn't support login with apple id yet. So anyone faced any issues with review recently.
As confirmed in the comments by @Thilo if app provides non third party login option then app will be approved, this rule is applicable only for the apps which is having exclusive third-party option.
App got rejected, even though there were both options available
@Emil is your app having login using your own server option, then it should be approved for e.g. Example app is having login option using example.com api, it should be approved, if its available you can add comment in the review section and resubmit for the review.
they've ignored my statement. Also I'm not the only one with this issue stackoverflow.com/questions/59225567/…