present viewcontroller on top from app delegate - swift

Question

so i've spent the last 5-6 hours trying to get this one feature to work and i've run into a couple of pitfalls in my implementation and limits of understanding. I've tried a couple of methods:
Method 1 :
func applicationWillEnterForeground(_ application: UIApplication) {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
self.window = UIWindow(frame: UIScreen.main.bounds)
let storyboard = UIStoryboard(name: "Main", bundle: nil)
var vc : UIViewController
vc = storyboard.instantiateViewController(withIdentifier: "PasscodeLockVC")
self.window?.rootViewController = vc
self.window?.makeKeyAndVisible()
print("app entered foreground")
}
Issue : I can't dismiss the screen from the PasscodeLockVC (it's the passcode VC).
Method 2 :
public extension UIViewController {
func show() {
let win = UIWindow(frame: UIScreen.main.bounds)
let vc = UIViewController()
vc.view.backgroundColor = .clear
win.rootViewController = vc
win.windowLevel = UIWindowLevelAlert + 1
win.makeKeyAndVisible()
vc.present(self, animated: true, completion: nil)
}
func hide() {
dismiss(animated: true, completion: nil)
}
}
Issue : I get a black screen when i dismiss.
**So my questions is ** Can someone direct me on the best method to have my lock screen present upon entering foreground (i know it goes in applicationWillEnterForegroud), but when i do so, it preserves the screen that was active when the app was closed (will all of it's contents since it's a diary app)? I've been stumped all day and could really use some direction.
Running on most recent Xcode