Kindly refer to this -> "Your Swift Playgrounds app project must be built with and run on Swift Playgrounds 4.0.2 on iPadOS 15.4 or Xcode 13.3 on macOS 12.3. If it runs on iPadOS, it must be optimized to display properly on all models of iPad Pro. You may incorporate the use of Apple Pencil."

Click on App -> General -> Pricing and Availability -> edit All countries or regions selected

You can try google chrome or sign in via private window and sometime you can't really see the loading view just wait like 1 minutes it should show up.

request user to review your app after certain events, look into it and improve the app. Keep doing this when your app's good it will automatically be ranked.