[wrxtasy]

I'm looking to buy a Kodi box from the 11/11 Single's Day sales. I expect it to support 4K video playing from a NAS (bitrate iPhone videos 54 Mb/s to DJI videos 100 Mb/s). The gigabit connection is a must, either built-in or with a USB adapter. Which one would you recommend?

Exactly what type of 4K ?
4K HDR to a 4K HDR capable TV ?

Plug n Play or DIY with LibreELEC / CoreELEC ? 

 Thanks for the reply. 4K HDR support would be preferred... given I'm looking for a low price it it's probably LibreELEC, the price should be about 50-60$ max.. even lower if possible.

$60 Max.
You are likely looking at a Gigabit equipped - S912 Tanix TX9 as found over HERE

The problem is all the cheaper S905W, S905X devices have no Gigabit ethernet and usually much weaker WiFi.

If you need a better remote then grab the USB dongle Mini receiver, Wireless (NOT the Bluetooth) one from ......