Well said! I will go one step further…without network optimization, you’re not hearing full potential of your streamer or server. It is so vital to clean up the Ethernet signal from your modem or router before it enters your streamer/server. Even if your streamer/ server is galvanically isolated or use superior noise rejection circuitry, using some kind of noise filtering device is proven to be helpful in cleaning up the grunge. The degree of improvement from noise filtering devices may vary in each setup but they are generally effective. Please don’t go gadget crazy…IME, one or two high quality noise filtering devices are more than adequate, atleast that’s been true in my system.
Everything matters, starting with network optimization, high quality LAN cables, streamer/server and DAC. One other thing that is not often mentioned here is Grounding - passive or active. Grounding your components appropriately can have very profound effects on overall sound of your system by way of lowering the noise floor.