Linux Gaming

Hi all, I have an HDR capable monitor, HDR enabled in KDE plasma, but I still can't get some games to let me switch on the HDR toggle. Every time I turn it on in the game, it says something along the lines of "your hardware must support HDR" or some shit like that. After some online searching, I was able to enable it on ONE game in the heroic games launcher with (I think) a launch command? Where I threw there a "--HDR" and some other strings in there after enabling gamescope (this is where shit starts to confuse the hell out of me), then the game let me actually toggle HDR on. I can never do that on Steam. I am trying to play Indiana Jones and the great circle and it says the same. Same with Resident evil 4.

How do you do it? Is there a guide or something to follow? Is it like per game? Like some games allow it and others don't? Also, and most importantly, how the hell does gamescope work? On heroic, there are things like "Game width, game height, upscale width and upscale height". On Lutris, there is a cleaner way with dropdown menus where you choose a "Output resolution" and a "Game resolution" resolutions. What are those? Which is which? Sorry for the very long post, and I appreciate any help Thank you