I’ve just discovered that the PlayerController has a CheatManager:
It contains the class used for the debug camera. By assigning the PlayerController a custom CheatManager child class, and assigning it a custom DebugCameraController child class, I can bind inputs in my custom debug camera Event Graph.
So in your current situation, if you override the CheatManager and its Debug Camera class, you can add an Input X node inside this new camera’s Event Graph.