Sounds like the same problem many are seeing. Modern routers often include a feature which reconfigures WiFi on the fly, reassigning devices to better WiFi channels for their operation. But Roon sees such a reconfiguration of an endpoint (like a phone) as a broken connection, freaks out, pauses everything, and rescans the network.
I’d look at the Roon logs first, to see if this is what’s happening, then look at the WiFi configuration section of the router UI to see if there’s some “feature” which can be turned off.