is 7800x3d worth it at 4k?

I posted this in r/buildapc too, but since i mostly play X4 id like your opionion..

Need help deciding boys. Currently I've got 3600x with 3060TI, I'm planning to switch to 7800x3d + rtx4080. I've got 4k LG C2 monitor and the games i play are X4 Foundations, Cities skylines, Warhammer 3...

In the reviews I see that at 4k there's not much difference between different CPUs?

Can someone please explain it to me?

EDIT: 4080 price here is 1400eur, 7800x3d likely 550eur and 5800x3d is 370eur for comparison