You are 100% correct @Jonas_Soderlund.
A good router does make the world of difference with reliability. It’s amazing how many people accept the junk they are given, once they run in to issues. Saying that, the out the box one we got from our ISP, previous & now the newer gen model, have been bullet proof, even on what is essentially high speeds for here in the UK. I guess having just about everything in the house hardwired & having very limited kit will help vastly though.
I know from previous experience however, Sky routers tend to have some severe issues across various kit and simply replacing with Netgear or Linksys sorts 99% of the problems 99% of the time.
Because I’ve tried a couple of other ways to stream from Roon, I’ve fortunately narrowed it right down to the CCA being the issue here. I do plan to change the router to something far better when we next do some home improvements but will have a shiny new streamer way before that 
Best wishes,
Tom