As the title asks, how does one actually use HDR for games after upgrading to Plasma 6?

This was the feature I was most excited about, and I can hit the HDR button on my display configuration and it looks like the desktop is going into HDR mode, but so far I have had zero luck enabling the HDR feature in games. Every game I've tried had the HDR toggle disabled with no way to enable it.

I am running these games under Proton and I've tried both 8-GE and 9 Beta. Any tips?

Edit: probably important to note that I am using an AMD GPU under Wayland