I went from a 10600k to a 13600k with a Rtx 3090, same as you. I honestly cannot say there was much of a difference, Because with 4k your running lower fps which loads the cpu less.

I think I had less micro stuttering but that’s about all I can really figure.

Longer term the 13900k will be better. the 14th gen is a joke for the most part in that its basically the same cpu’s with a higher base clock.