I haven't tested it myself, but you'll need to install gamescope and the Vulkan HDR layer, then set the launch options to use it.
Of course, you'll also need a monitor that supports it, and a cable that supports it as well (I recommend using a DisplayPort 1.4+ cable).
Edit: Here's a detailed how-to: https://zamundaaa.github.io/wayland/2023/12/18/update-on-hdr-and-colormanagement-in-plasma.html