[polarrys]

Given that your display will re-sync between displaying a 2160p60 UI and 2160p24 content, is a 1080p60 UI either side of 2160p24 media playback a major issue?  Or is a 2160p UI a must-have?  

The big source of 2160p50 and 2160p60 stuff will be UHD TV sport streams - with BBC iPlayer already running 2160p50 HDR streams that can be played in Kodi during live events like Wimbledon Tennis, World Cup Football, FA Cup Football etc.  It's widely expected that Tokyo 2020 will be UHD HDR on BBC iPlayer too - so that is one thing to aim for.  However I don't know how well supported HLG is on Intel/AMD platforms - all the reporting seems to concentrate on HDR10 and Dolby Vision (neither of which are in widespread use for live TV)

Odroid N2 and Rockchip 3399 stuff both support 2160p50 HLG in CoreElec and LibreElec respectively though.   

Dear noggin
Thanks for your post. 
For me , kodi interface is in  4096x2160@30Hz and the result was extremely good. I will wiat for futher upgrade about HDR.   

I'd disable 4096x2160 modes in your Kodi whitelist, and avoid running your UI in that mode.  There are no 4096 native LCD or OLED TVs (*) on sale in the consumer market - all panels are 3840x2160.  As a result a 4096x2160 UI will have scaling artefacts as it is scaled to 3840x2160 for display.

(*) There 'may' be some 4096x2160p projectors I guess in the consumer sphere - but there are no mainstream 4096x2160p sources that I'm aware of (all consumer sources are 3840x2160) 

noggin you are right. My TV accept maximum 3840x2160. I will change the setting on Kodi to have 3840x2160.

Thanks for the advice