Neon Tower

For Android:

https://www.makeuseof.com/use-android-phone-as-controller-pc-games/
https://www.youtube.com/watch?v=h4PHCalvjMM
https://www.instructables.com/MAKE-YOUR-ANDROID-PHONE-INTO-GAMEPAD/
For IPhone:

https://www.makeuseof.com/tag/turn-your-iphone-into-a-gamepad-with-joypad-legacy-mac-windows/
https://getnotifyr.com/how-to-use-your-iphone-as-a-game-controller-for-your-mac/
https://www.wired.com/gallery/best-mobile-game-controllers-for-iphone-android/