Please read my full post before responding. Thank you for your consideration.
With a recent PowerApps change https://powerapps.microsoft.com/en-us/blog/new-properties-for-responsive-canvas-apps/ it's already possible to use one single PowerApp to accomodate both phones/tables in landscape/portrait configuration and send the user to dedicated landscape/portrait screens (screenshots from Studio in Chrome, and same PowerApp opened on Android device starting from landscape/portrait orientation of the device).
However, navigation to dedicated landscape/portrait screens using Navigate can currently not be triggered by the user turning his device (or resizing his browser windows)
Hence, I propose adding App/Screen OnRotate/OnResize events to cover this case as well.