A good streamer will bring you great sound .
I would use a wall wart wifi extender plugged in next to your system upstairs. My $150K system works this way. Good streamers make up for network shortcomings. I have tried ether regenerators and different routers and they have had no noticeable differences in sound quality. I know of many $100K systems working this way. I really like Aurender streamers for their great sound quality at every investment level. They are excellent at isolating the system from the network. Although there are many streamer brands available.
There are two approaches to optimizing streaming, one is an inexpensive streamer and do all sorts of things to the incoming internet…special routers, switches, running exotic cables or get a good streamer. The later does not require lots of IT knowledge and is simple. I was in IT for nearly forty years… I am happy to leave that behind. Also, consumer network equipment tends to be incredibly unreliable… so best to avoid putting lots of money into it.