If you use Valve’s game mode, (which is possible to get either using steamos, bazzite, chimera OS, nobara, or you can manually set it up. You should be able to get it to work. This should work for windows games that support HDR. AFAIK there are no Linux games yet supporting HDR. It should be possible to get videos playing with HDR also, but that would be an exercise for the reader, or wait until people make it easier.

gamescope is what you’re going to want to search for if you’re attempting this exercise. I just set gamescope in the launch options for the games where I want HDR.

Wayland has had HDR support for around 6 months (using Arch, btw, so YMMV depending on how current your distro is). The issue has been that there is no way for an application to determine if your hardware supports HDR because Wayland doesn’t have color management protocols.

The Wayland color management protocols are done and are targeted for the next major release of Wayland (in a month or two, roughly). In the meantime, in applications that supports it (like mpv if you want to watch movies) you can launch it with ENABLE_HDR_WSI=1 to let it know that your setup can use HDR. Once the protocols are released you won’t need to do this.

You can edit/create a .desktop file for HDR mpv like so:

Exec=ENABLE_HDR_WSI=1 mpv --player-operation-mode=pseudo-gui --vo=gpu-next --target-colorspace-hint --gpu-api=vulkan --gpu-context=waylandvk -- %U

Here’s a link to the topic on the Arch wiki: https://wiki.archlinux.org/title/HDR_monitor_support

TL;DR: Official support in a few months. But this is Linux, so you can get things sooner if you want to tinker.