To answer your question, as you are going from your router directly to your single streamer, a high end ‘switch’ may not be necessary. I had the same question, and was advised to get 2 Media Converters, tethered with an optical connection : Router > 1st Media Converter > 2nd Converter tethered with optical > Streamer.
This helped to ‘strip’ unwanted noise from the router, and indeed sounds better. All in? About $100 via Amazon. I’m pleased with the SQ increase.