Here what I have done, not sure if I can improve without significant cost?
COX router, WiFi disabled, connected to separate switch and router. 20ft blue jeans cat 6 to stack audio smoothlan, then 1.5 m DH Labs Ethernet to streamer and DH labs USB to DAC.
All audio equipment except amp plugged into Equi=Core 20 amp balanced power supply.
Home wifi has 2 access points, both about as far from the listening room as they can be.