Worse perfomance on a smaller monitor/resolution

I went from my 5120x1440 which ran at a consistent 80-90 (sometimes 70) fps

then I swapped to my 2560x1080 and now I am on 60FPS

I see it's my CPU have the higher % usage

I'm using the medium preset graphic settings and I read a bit of the perfomance guide they released - but I'm honestly just dumb :')

anyway to make it use more of my GPU on the smaller resolution?

CPU: i9-129000K 16-core
GPU: Asus Prime OC 5070 12GB