If Node you're all in one unit, not much to do, you can even use wifi.
Something like NUC's with separate dac are next step up from Bluesound. At this point network optimizing can pay off. Basic setup will usually be server/streamer all in one package with usb out to dac, usb renderers are first optimization. The issue with most usb outs is they come directly out of motherboards, not ideal, reason why people find usb renderers effective.
Next people generally move to network optimization, which means fancy switches, filters. I'm just proposing another path for optimization, simplifying while employing optical conversion.
My proposal for optical with shortest signal path would be optimized optical out on server to optical usb renderer/end point/streamer (whatever you want to call it) to dac. This is optimal isolation, read lowest noise floor, should be highest resolution streaming solution.
Since optical out servers are practically non-existent one has to do the fiber media converter dance,
Some people want to stream for convenience, others seeking highest possible sound quality. Many good choices for convenience, have to get into weeds to achieve highest sq.
My take is most off the shelf servers not for me, too little bang for buck, no two ethernet out (with exception of Antipodes, SMG), don't render usb internally and only the very highest end ones will do HQPlayer high level processing. One can do much better with diy atx build, possibly NUC build.
Highest quality streaming dac can also be another top choice, forget the usb altogether, all you need is optical for the isolation. On some dacs I2S may also be best input, again don't have to worry about the usb stuff, optical is all you need add. Unfortunately, most dacs optimized for usb, rendering and optical both needed for best streaming quality..