I can’t say with complete confidence, but since HDR support in linux is fairly new and DolbyVision is a proprietary standard, you’re probably out of luck when playing the files directly.
However, since you have an apple tv, you can set up a media server (be it jellyfin, plex, emby, DLNA or even a simple SMB fileserver) and stream to the apple tv via a media player app that supports DV. The easiest setup would probably be plex.
Ah. That makes it a little more complicated, of course. Otherwise, I‘d have suggested getting an old second hand 5.1 audio receiver with S/PDIF input and using your TVs digital output (or an HDMI audio extractor if it doesn’t have one) to get the signal to your speakers.
Receivers like that are usually very cheap. I’ve seen them go for less than 10€ in perfectly working condition.
But good that there’s a solution to get DV working. The Linux community never seizes to amaze me. Good luck implementing it.