I'm not watching movies in Linux, I don't really care about HDR, but I've had nothing but horrible experiences out of video editing products in Linux. If it's not a skin for FFmpeg, My project has about a 10% chance of making it through to usable output.
I used the limited HDR capabilities of my monitor (VA panel with no backlight zones I can spot) in some games, it's somewhat better than in normal mode, otherwise I just use SDR to save power.