2160p mode on a PC, is it possible?

i’ve recently upgraded my 1080p HTPC to 4k. Prior to the upgrade when I played a movie on my 4k LG OLED TV it showed as 1080×1920@60hz in desktop mode but when playing a movie it would switch to 1080p@60hz or 24hz depending on the movie being played. It switched from desktop mode to movie mode and therefore I could have a different TV profile for each mode. This was important as WARM2 which is essential for movie playback is too yellow for desktop and web use. So I had warm1 set on one profile and warm2 on the other and everything in the world was good.

Now, I expected the same with 4k. In desktop mode the TV inf shows 3840×2160@60hz as expected but when I play a 4k video it doesnt switch to video mode, 2160p@60hz, it doesnt do this at 24hz either so I am stuck with one profile for desktop and video playback. Of course I could still switch profiles manually but I always forget to do this and its just anoying.

is this a limitation of the current crop of 4k TV’s or HDMI 2.0a specs ? does anyone else have a 4K HTPC that can advise if they are getting 2160p showing on their TV info bar or 3840×2160 like i’m getting?

cheers.