I was using a 30' CAT 6a cable from my hub to my streamer and recently switched to isolation using fiber endpoints and a short CAT 8 (LinkUp) cable. The upgrade was significant on my system. Guessing there was more noise than expected on the old line and it was affecting the sound/signal.
Given the distance you are covering with your system, this might be a good fit. It is cheap to try, about $100. There is thread here on AG discussing it and recommended components.