ETHERNET CABLES

Of course their is a sq difference in a better cable, including Ethernet cables.

In the past, I tried the top of the line blue jeans interconnects to see what all the talk was about and to compare them to my reference cables that cost many times more. I gave them a month (I knew in a minute but wanted to see if they would burn in). I sold them. No comparison to my better cables. 

Ethernet cables do not make sonic differences

If only that were true, life would be grand. 

I second the fiber media converter tactic.  It makes a world of difference in the sound. 

I too work with computers and in fact, I work with highly complicated global networking.

Guess what? Cables absolutely matter and the correct cable for the correct application is critical.

I echo the comments about sticking with Cat6 - I have used Audioquest Pearl Cat6a and the results were very good.

For a cable run that long you should consider the recommendation around a fibre run however the claimed isolation benefits are reduced as the 10GTek devices are very noisy, especially their cheap-as-chips SMPS (I've trialled a pair of 10GTek's and they aren't great, very cheaply built). Alternatively, look at using Powerline Ethernet Adapters with passthrough sockets - they can yield great results. TP-Link adapters are very well made.

If you want to get into fibre in a quality way consider using Cisco switches with Cisco SFPs as they have very high-quality internal power supplies for serious data and voice applications and are intrinsically less noisy.

With all of this said, my sound quality improved the most when I switched to using a wireless network bridge (ifi Zen Stream) with a quality WiFi circuit connected to a high-quality WiFi router (TP-Link Deco). For me, this is the cleanest (less cabling mess) and sonically best solution.