Here we are almost 24 years into HDMI/HDCP and it is still trivial to make a bit perfect copy of 4K stream, and even easier to rip a 4K Blu-ray. I'd like to say the studios mostly failed, but there would be common consumer devices for copying movies, just like there used to be dual cassette tape decks for copying tapes.
I've only done one, but it was the same process as a regular Blu-Ray. The drive I already had was compatible.
The hard part I'm having is playback with all the bells and whistles. Afaik, support for HDR10+ output on computers is sketchy, but blu-ray menu support on playback platforms (android tv, webos, tizen, roku) is non-existant. Anyway, most devices top out at 100M ethernet, which is below the max bitrate of 4k blu-ray (peaks of 150Mbps). I've heard good things about Apple TV, but also that it's very difficult to manage unless you've got other Apple products, and my Apple IIe doesn't count.
I have a 1G Android TV device, but it still stutters in playback of high bitrate scenes when I ripped to a mkv.
I regularly play UHD HDR content I ripped from my blu-ray collection to my 4k AppleTV over 1Gbs Ethernet. I use the Infuse app instead of Plex, no stutters, no issues, looks great!
sidebar: I've had a lot of problems with the AppleTV plex app, it does not play some HDR content well, or at all. Plex on my nVidia Shield works well.
Both of my LG Blu-ray drives rip 4K discs as easily as standard 1080p discs.
My workflow is a script that calls MakeMKV's CLI with the settings I use every time. Then I run that through Handbrake to make a reasonable sized file. Just a handful of clicks.
Having a recent-ish (RTX 2070 Super) really helps as the NVenc H264/H265 engine is blazing fast (100+ fps), and is the first hardware encoder I've used that always beats Handbrake/x264 for quality and filesize.
