Think everyone needs to read this, to get a fundamental understanding of how ethernet works.
https://www.techtarget.com/searchnetworking/definition/packet
It's so different from an audio signal, noise can not piggyback on a packet. Ethernet jitter will not affect sound like audio jitter. It's completely different. Jitter in e-net can just slow down transfer, in worst case just have the packets be retransferred, greatly slowing down transfer.
IMHO, when someone gets a better PS for a switch, the increased in sound quality, might just be from removing the noise from the home power. I can see where if you have a crap PS, and get a clean PS that maybe the router might be able to process things better, or just work a bit better in general.
Money is much better spent in just getting certified CatX cables instead.