Open new document in SwiftUI on iOS

I have a SwiftUI document based app. The iOS version has a Scene Delegate:

class SceneDelegate: NSObject, UIWindowSceneDelegate 
{
	func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>)
  {
		for context in URLContexts
		{
			let url = context.url  // url.scheme = my custom scheme
      let text = ... extracted from url ...
      // I want to open a new untitled document with text
      // but 'newDocument' has been explicitly marked unavailable for iOS
    }
  }
}