WiFi Streaming Versus An Ethernet Cable Connection

If you have Fiber optic cable (with LPS on FMC’s) between a mesh router and network streamer will an LPS on the router or high end cables make an improvement?  I have tried several levels of ethernet cables (Audioquest, Pangea, Amazon, blue jeans, Chinese Nordost Odin in copper and silver plated) and have not heard a difference.  Ended up using a copper Cat 8 shielded from amazon and returned or sold the others.  Is it just me and my systems or does it not matter?

Based on your description, I would try to add an Ethernet switch between the router and the Bryston. I don’t think what you are hearing is noise (so the passive filter won’t help), it’s more likely the poorly timed data coming out of the router. A switch will re-clock the data so the Bryston will have an easier time re-clocking it (again) before it sends it on to the internal DAC section. No need to spend a lot of money at all. Try a Netgear GS108E from Amazon for about $50 and add a short Auduoquest forrest Ethernet cable between the switch and the Bryston also from Amazon. Listen for a few weeks and if it doesn’t help, send it all back. If it does help, either keep it or upgrade from there with an audiophile-quality switch and an even better cable from Audioquest or something like the DH Labs Reunion Cat8. 

@mrskeptic seems like packets are only half the equation here.

You guys must all have golden ears lol. I can’t hear a difference. There is sometimes (often maybe) an advantage to not wire things together as noise can travel from one device to another. I once had the hum of a plasma tv bleed through my entire system. I switched to a projector in the end. 
 

Anyway I would think Wi-Fi would help stop noise bleed. Fiber optic would do the same. This is why I liked the old school macs with toslink out. Stopping the noise was more advantageous than the added jitter of the toslink vs USB. 

What you've got is already as good as you can get.  "Audiophile" network cable is for suckers.