I can answer that: I've used plenty of apps the past decade that tried to do this and each and every app "felt wrong". You know it within seconds that an app is not using native UI. There is always some basic interaction missing or just not working. Be it something simple like swiping navigation from the side of the screen or text fields that just do not work as expected.
Isn’t this the same logical error as saying “I can always tell when someone is wearing a wig”? You are only counting the times when you can tell.
No, because you can see when a website is using design components that imitate a particular platform (iOS, Android), like Ionic. Because the UI elements wouldn’t naturally look like that on a website if it wasn’t. They would look like standard HTML form elements.