As a UNIX guy I really don’t have much skin in the OSX vs Windows game as far as an HTPC goes (I use a jailbroken Oppo, Chinese Oppo Clones, an Apple 4KTV, a couple of home made ZFS NAS systems, Plex, an AVR, and one of the last passive 3D 4K TVs - no HTPC, although technically the Oppo‘s are running Linux). I am, OTOH, very interested in Virtuoso software on both platforms as a poor man’s (far cheaper) Realiser A16. It certainly checks many of the boxes, and perhaps can be even more immersive because of better head tracking support (I’ll know more after I play with the tracker that just arrived). Having gotten Virtuoso working on both my OSX and Windows boxes, I will observe that it’s easier to get going on the Mac, but it works fine on both platforms.
Don’t get me wrong, I love my A16. But it is not an option for many.
For what it’s worth, my Mac is an M1 Mini, with a pair of 4K displays. I don’t have a Netflix 4K subscription but I gather from support pages that I could indeed bring up 4K Netflix in the browser if I paid extra. The built-in Atmos renderer in the Mac OS sound system works great and beats having to deal with DRP and the like on Windows.