Cleaning up ethernet ahead of the streamer (InnuOS Zenith Mk3)unfortunately is a lot of trial and error. In my case I started by adding a Zerozone power supply to my Etherregen and using an Antelope10m clock to reclock. I subsequently added DXE filters and a LHYaudio LPS/reclocked switch ahead of the Etherregen. Furthermore switching from thin gauge cat6 to heavy gauge cat 8 Onti cables with Telegartner connectors made a big difference. A lot of people argue to go optical into the server. In my experience this results in an over analytical, thinned out sound. As a starting point upgrading the router and its power supply is equaly worthwhile.
It is frankly disappointing that after 15 years of streaming nobody seems to have found a universal solution, that said I am intrigued by the InnuOS Phoenix Ethernet.