Check that Linux actually supports HDR on your setup.

Ventilation. Probably depends a bit on what hardware you land on, but that era of case wasn't exactly designed with airflow in mind.

If you just want Bluray ripping/playback any modern AMD APU should do the trick. Playback/ripping of media is a largely solved problem. Either it has the decoder/encoder built in and the CPU sits idle, or it doesn't and the CPU/GPU go crazy trying to play it back, and even longer encoding.

That said HDR sucks balls on basically everything but the highest end displays. HDR on a "conventional" IPS panel looks awful because it just cranks the brightness up to 100% and your blacks end up looking like greys thanks to IPS' mediocre contrast levels. IMO HDR is only worth it on OLED displays. Mini/micro LED displays with a TON of zones can look ok, but it needs to have at least quad digit dimming zones. According to google the MacBook pro has 2,554 dimming zones and it's display largely doesn't bother me. That's at only 16 inches.