@sls883 Routers are generally the noisiest component in streaming chain, general use network switches don't offer galvanic isolation. As for switches, I''m not alone in finding them redundant and of no benefit, this with audiophile switch. Long LAN cable runs not the issue here, optimization of connectivity is where galvanic isolation comes in, optical is superior in this regard.
Like everything else in streaming chain, optimal implementation of every component in chain required for optimal sound quality. Cheap FMC is not even close to hearing full benefits of optical conversion, this assuming one has quality streamer and dac.