How to collect a user's real email address when using Sign in with Apple and Private Relay?

I’m using Sign in with Apple in my iOS app.

When a user chooses “Hide My Email”, I receive the @privaterelay.appleid.com relay address. For marketing reasons, I would prefer to have the user’s real email address instead of the relay email.

I want to stay compliant with App Store Review and the Sign in with Apple design/UX requirements.

My questions are:

1. Is it allowed to force the user (as part of the registration process) to provide their real email address, even if they chose “Hide My Email” during Sign in with Apple?
2. Are there any specific App Store Review guidelines that forbid:

• Blocking sign up or access to features if the user keeps the relay email, or
• Showing a strong prompt like “We can’t log you in unless you share your real email”?

1. What is the recommended, compliant pattern for collecting a “real” email when using Sign in with Apple + Private Relay?

I’d appreciate any official clarification or examples of what App Review considers acceptable vs. reject-worthy here.

[Re-Titled by Moderator]

Original Title: Sign in with Apple