[wrxtasy]

If you need to view properly encoded 4K HDR content your only option is the nVIDIA Shield as it can access 4K HDR from Netflix and Amazon services.
It will run Kodi Krypton or SPMC (Kodi Jarvis) once you download them.

But there is this 4K Android OS problem:

The 480/576/720/1080p > 2160p(4K) Android Upscaling issue

There are now numerous reports of Soft Picture output from Android media players when Android Resolution settings are set to 4K and 480/576/720/1080p content is viewed from Kodi Krypton and various Android Apps.
Kodi Media Player - Hardware Upscaling of 480/576/720/1080p > 2160p video is simply not as good compared to using the superior quality upscaling hardware in modern 4K TV's.

The problem is 99% of Android media players (excluding the FireTV2) cannot dynamically switch Resolutions on the fly. Ideally you want the media player to switch to 4K when playing back 4K video content only and let the TV upscale all the rest of the video content.

For Kodi Krypton use only - the solution to this is to use LibreELEC Kodi on an AMLogic S905 where both dynamic Refresh Switching AND Resolution switching work seamlessly.

There is no LibreELEC on the Mi Box or the Shield at all.
Decent 4K media players with Official Support from LibreELEC are the AMLogic S905 - ODROID C2 or WeTek Hub / Play2.
Otherwise get any old AMLogic S905(x) box that will partially handle 4K HDR content as well.

I'm not sure how mature LibreELEC is on the 4K capable "Lake" series Intel Hardware. I believe there are issues at the moment.

NOTE: SPMC (Kodi Jarvis fork/version) on the nVIDIA Shield can use the Lancos3-Optimised upscaling method to produce decent video quality results at a 4K resolution. This is the SPMC App only. There is no Lancos3-Optimised when using Kodi Krypton or any other Android Apps.