I wouldn't blame you if you didn't bother with HDR. While the effect can look spectacular in the right game and on the right monitor, anyone who's regularly tried to use the feature on PC over the years will grump and grumble about manually turning it on and off, why in some games it works well and others not, and why a modern gaming PC can't seem to reliably tell a monitor that its displaying HDR content without some user prompting.
GameHDR is currently designed for Windows only, and has apparently been tested on Windows 11 23H2. I tested it out myself with my personal Win 11 system, and found that the app did… precisely nothing. I could run it, and point it at an executable, but when I clicked the create shortcut button it didn't. Boo.
Unfortunately, once GameHDR has started the executable and told Windows via a Powershell command to enable HDR, it appears to consider its job done. Then, once the next link in the chain begins, HDR turns off again. Swing and a miss that one, at least in the few games we tested. Many others will likely work just fine.