I'm looking for any method (system edit, script, program, option) to disable the Guide button, and all button combinations that Steam intercepts in order to perform non-gaming related tasks, such as all media keys.
I don't know what the controller combos are but you can trigger all the media keys with just a controller. I've witnessed them all: mail, web, stop, play, pause, back, forward, etc. Combinations also open up Big Picture (not in a functional state though), Steam keyboard, and the like, but, obviously, in the middle of a game absolutely none of these are interesting to me.
I only want the general in-game controls (moving my character/car, etc.) in-game, as well as outside of a game, because when I'm not playing, I'm not using my controller but a mouse and keyboard.
The idea that I'd want to use my controller for desktop tasks should not be assumed, which is what Valve seems to do.
Disabling "Guide button focuses Steam" in the Big Picture controller settings does not work. It only prevents that action specifically, and not the rest. And to make matters worse, this option turns itself back on from time to time.
I don't know what the best solution for this would be, because it seems Steam interprets them the wrong way. That's why I'm afraid that this is something that requires modding the Steam app itself.
Any ideas for a simple solution?