Step 1: use appletv 4k
as much as it pains a certain set of nerds, using a dedicated stream device is still the best way to bypass the arbitrary hurdles that streamers throw at you. To build a general pc that gets Dolby vision and atmos working right requires at best some very specific hardware/software choices and at worst sometimes just don’t work at all on pc (unless you are willing to do things like hackintosh).
The audiovisual space has just always been intensely proprietary, even something as basic as divx was something you paid for or pirated back in the v3.x or v4.x days. Same story as HEVC: Fraunhofer and Dolby have been grubbing for licensing fees for decades now, and you either pay it or spend some time working around it. And if you’re a corporation then you just don’t ship that feature in your product.
Apple also does a really good job implementing those features at the margins, Apple TV is a nice device. But even if you buy (eg) something like a shield tv it’s gonna be easier than tilting at getting Netflix to send you a 4k stream on windows 10 or Linux. At some level it is platform discrimination plain and simple - they just won't send full-quality video to "open" platforms and you can either deal with it or go full pirate. Sometimes they won't stream it even if you have widevine set up properly etc - and it's all completely arbitrary and they could break it tomorrow. Or you just buy an apple tv/shield tv.
Plex, Infuse, and VLC also let you interact with plex/jellyfin on the apple tv, and there really is no question about what it can decode, the answer is "basically everything you'd interact with as a consumer", short of weird stuff (idk about something like 4:2:2 or ProRes). Ironically the A17 also might be my fastest processor (in single-thread) at the moment, lol - definitely faster than my laptop, might be faster than my gaming desktop.
Sucks but that's how it is - to this day, AMD doesn't have working HDMI 2.1 support on linux, because HDMI Forum won't do an open license. You either have closed-source blobs or firmware that implement it, or you don't get the feature. These are hard problems, and people expect to be paid to stare at them. And once you spend the time getting all the software and hardware vendors and studios onto the same page and then implement it etc you're going to want to be paid for that too.
It is one of the real problems for the linux kernel imo - not everything can be GPL licensed all, and (for obvious reasons) there is no escape valve for "ok but this vendor is really proprietary and the feature is really important...". When the unstoppable force meets the immovable object what you get is both vendors shrugging their shoulders. You want to fuck with NVIDIA over whatever GPL symbols? Then I guess you won't have HDMI 2.1 on your platform at all, then - because AMD's not gonna win that battle on licensing. The bulli approach worked with ZFS because ultimately there's diversity in filesystems, but if your hardware works best with HDMI 2.1 then you really don't have a choice in the matter. The very popular RDNA2 cards only have DP1.4, for example, so if you don't get HDMI 2.1 then you lose half the bitrate the card can support.
https://gitlab.freedesktop.org/drm/amd/-/issues/1417
Anyway you can tilt at that, or... pay $125 for a refurb ATV4K ethernet 3rd-gen and go watch a movie. It sucks but that's kinda the reality of the space - it's only troublesome if you aren't willing to grease some palms to make the system work as designed. Do you want to consoom or not?