My desk surface is usually so cluttered that the keyboard cable is the least of my worries most days.
I use a straight, braided (non-coiled) cable and run it straight from my keyboard off the back of my desk. The cable routing under my desk is clean; I use wire trays attached to the underside of the desk so all the wires are tucked up and not visible under the desk until they all drop down to the PC in a bundle.
I haven’t done it yet but my goal one day is to have a desk with aviator female ports in the surface and then have cables with 90deg connectors to connect my keeb and mouse. This isn’t my image but it demonstrates the sort of thing I’m on about
I wish my desk was so neat! I think what would be nice in your setup, would actually be a coiled cable off to the left, and then to the back between the watch charger and the foot of the iMac (it’s so neat and the cable crossing the base is just like a little annoying fly in the soup for me ). But anyway, just an idea!