No doubt streaming is big rabbit hole, so many variables!. But the more I experiment the more I become convinced simpler is better. This has certainly proven to be true on network side of thing, although I continue with two computer setup, separate server and dedicated streamer.
Most insightful experiments have been with the beginning stages of network starting at feed from ISP into the house. Locating modem close to system, extend coax cable vs long runs of ethernet. Broadcom chip based modem vs Intel chip modem, Broadcom less jitter, also modem with external power supply so can use LPS on modem.
Now experimenting with removing wifi from audio streaming chain, already disconnected antenna from server. Two ways to go here, present experiment with enterprise level router (no wifi) will have feed that serves audio system only, another bridged feed goes to Netgear wifi/router for wireless devices throughout rest of house. Point is to get wifi and all it's attendant emi/rfi out of audio chain. The other way would be to forego wifi altogether, simply use audiophile switch in place of wifi/router. Point here is wifi/routers are likely the noisiest device in most streaming chains, getting out of audio chain should pay off in lower noise floor and jitter. Seems to me adding audiophile switches to chains while maintaining wifi/router upstream is a band aid at best. What's upstream of these switches is entirely critical to streaming performance, one can never get back what they lost with long runs of ethernet, bad modems and wifi/routers.