Network Switch

A switch is the upgrade to a hub.  It's not really an audible benefit.

What a switch would allow for is multiple separate communication streams.  Useful in business when you have A talking to C and B talking to D.  The Switch would allow those 4 devices to communicate in isolation and at maximum throughput.  Otherwise, A, B, C and D would share the same bandwidth, slowing them each down.  

However, if you have 3 devices streaming from the internet, the isolation benefits here are diminished. 

Still, switches are cheap, your modem has one built in, and it's been years since I even saw a true Ethernet hub as opposed to a switch. 

@erik_squires 

Thank you. It appears I can sit tight.

you won’t know unless you try it. we can reason and type and read all day...

these questions are only answered by doing the work to set up a proper experiment and listening

Try this switch @tcutter under $20

http://TRENDnet 8-Port Gigabit Desktop... https://www.amazon.com/dp/B09VYGPHW4?ref=ppx_pop_mob_ap_share
 

In my system it lowered noise floor and reduced harshness. 
Get the best possible Ethernet cable to feed the streamer. Doesn’t have to be super expensive. Wireworld Starlight 10 Twinax has a built-in filtering that also helps with noise reduction. Switch will regenerate the incoming signal. Some switches degrade sound quality. This Trendnet has no negative impact. Routers are noisy so this switch should be of help. 
You can also try a passive filter like iFi LAN iSilencer between router and streamer. 
https://a.co/d/0cePgdxW
 

I’ve wondered about upgrading my Ubiquiti lite 8 because it has unysed poe and unclear if its managed. I have another 20 or so devices non audio besides the roon, arcam, and appletv and prefer to isolate?