HDR is an issue. It just doesn’t seem to work right. Media players do all kinds of weird stuff. I’ve seen six screencaps from six media players taking snapshots of the same file, and they all had their colours wrong in different ways on Linux. VLC managed to get the colours right, but then lacked some other features. The Linux version of his previous media player uses different codecs on Linux so it suffers from the same problem.

Not surprising, there's zero HDR support on Linux desktop as of right now. You either need a player that can tonemap from HDR to SDR or you need to run your entire desktop through gamescope (which is what Steam Deck is doing).

However, KDE Plasma 6 releases next month and it's the first desktop environment to come with rudimentary HDR support. So things are evolving in that area.