I currently have Plex and Radarr. I only ever got 1080p content because that’s all my tv would do. Finally getting a nice new tv and would like to get a few 4K hdr movies to watch. Should I be looking for Bluray2160, Remux, or disk and what will Plex play?
It depends on what you want. If you plan on keeping two different libraries in Plex I would also keep two Radarr instances, but if you are going for a combined library you could stick to one and just use a different quality profile for the movies you want to be in 4K.
I do that since I like to have both libraries separate in plex and have duplicates.
1080p for remote streaming and low end devices, 4K for local streaming and approved remote clients only. that minimises the frequency of a forced transcode 4k-1080 stream, when a better looking 1080p native file should have been available.
a second radarr instance lets me manage that separately, but I have them synced to eachother.
If they have a 4K HDR capable TV they can playback HEVC. Does anyone even make x264 2160p releases? And container doesn't matter either, Plex will remux it for you if necessary.