Curd..Usually the Roon forum comes through. Good people there.
Your nightmare sounds like the cause may be something locally on your home network is interfering with Roon.
Do you have tens of thousands of files?
Have you rebuilt database?
Hard wired in is good.
Do you have any other internet related problems?
When you run speediest, what speeds to your typically get?
What switch are you using (doubt this is the cause)?
Have you reloaded Room.
What's the entire digital chain from the wall out please?
What are you using for a roon core? How many endpoints?
You are not using airplay, Right?

