I feel from where you are presently, a good Ethernet re-ganerator would be a logical step. I had good digital Ethernet and USB cables however when I added the EtherREGEN by Uptone-Audio, that made the most difference in cleaning up the noise and improving the micro-detail than any cabling changes I made. Uptone-Audio will soon be releasing their 2nd-Gen EtherREGEN device which I will be purchasing and either selling mine or giving it to my best friend.
Good Luck in your digital improvement decisions and search.