UPGRADE OR FULL NEW PC BUILD? Which route should I take?

I have currently a Ryzen 5600x with 32gb of ram, and a 6700XT GPU. I've had this PC for a while now, and I recently (2yrs ago) upgraded the ram and mobo, (previous mobo was having issues), I'm looking to get a significant upgrade on my CPU, to a 9800x3d, since I mostly play cities skylines 2 and I'm noticing that I'm only getting like 40 fps on my city, and even less when I have my browser opened on the side. But in order to upgrade my CPU, I'd need to upgrade my MOBO as well, obviously I'll keep the ram, can't afford new ones anyways, but should I get a new GPU instead as well? Or Am I just better off upgrading the parts I do have?