我也面临着同样的问题。并在这里找到了解决方案：重要性：在info.plist中，请使用外部显示会话角色（遗留），不要使用非交互类型！！！

func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        let sceneConfiguration: UISceneConfiguration

        if connectingSceneSession.role == .windowExternalDisplay {
            sceneConfiguration = UISceneConfiguration.init(name: "External Display Configuration", sessionRole: connectingSceneSession.role)

            // Removing the storyboard prevents the external display scene from being used
            if Settings.shared.externalDisplay == false {
                sceneConfiguration.storyboard = nil
            }
        } else {
            sceneConfiguration = UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
        }

        return sceneConfiguration
    }

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来源：https://hacknicity.medium.com/external-display-support-versus-stage-manager-on-ipados-16-149e15dc700e