That’s me out 
My Nova is fed from a basic WD NAS, into the router via a standard ethernet, into a powerline via standard ethernet, through the mains, into another powerline, out to a regular ethernet and into the Nova.
Despite all that and no dedicated hi-fi stand, the Nova sounds amazing.
In relative terms. How much better are ethernet cables going to make my hi-fi sound? Notwithstanding the router, powerlines and mains cable, what sort of gains are to be had?