@jeffrey125 , Someday.....lol.....that IS a long ride.
I’ll add my experience. I initially purchased the Network Acoustics Eno filter system. I had a 30 day trial period within which I could return it for a full refund. I had also ordered the English Electric 8 network switch but it hadn’t come in as of yet.
Candidly, I heard little to no difference with the insertion of the Eno filter and was going to return it. I don’t throw money out windows. But, as the company said it was important to upgrade the switch, I waited so I could audition them together.
Paired together, it was a clear improvement. Not night and day, but an improvement enough to keep the units. I did try the switch alone and while it made an audible difference, it was the pairing that brought the most benefit.
My point is that I did not fall prey to psychoacoustics or confirmation bias. I was about to send back the filter - which is designed to clean up the Ethernet signal from ride along noise. The network switch is working on the same concept.
What i think the OP is missing are two things: 1) few are disagreeing that the network packets arrive fully intact and that timing is a non-factor, and 2) noise (not hiss, but EMF, etc.) is carried along with the signal. This is because while the network is transmitting 1s and 0s, that signal is in the form of analog electrical pulses not immune to noise.
Hans Beekhuyzen addresses this in a YouTube video - and shows how this can be measured before and after the network switch. That we can hear the difference (not night and day, but audible) should be no surprise.
In summary, the data is bit perfect. The packets are in order and there are no timing issues being addressed by the switch. The upgraded network switches are doing nothing to the signal in this aspect.
Yet there is an audible difference between stock and some upgraded audiophile hardware because the latter is reducing the amount of other things carried along the ride. It’s not all snake oil (some is).
I would ask the OP to reconsider. While you appear to know far more than many of us about how networks work, perhaps that doesn’t translate into knowing all that is necessary to understand how sensitive digital audio conversion is to noise.
That’s why cables (all of them actually, digital, analog, speaker and A/C) are so audibly different.