Ubiquiti offers a broad selection of wide-area WiFi solutions, including their Edge series and, more recently, their Unifi-OS equipped network hardware.
Ubiquiti mesh networks offer users precise control over settings that can be optimized for your Roon audio ecosystem.
Reboot or reset your Unifi or Edge hardware.
See this guide for specific instructions on safely troubleshooting Ubiquiti hardware.
Enable IGMP Snooping
This setting is often available in the settings administration page for the Unifi/Edge router itself.
Connect your RoonServer machine to the main router with Ethernet
If your RoonServer machine is relying on WiFi or connected to a network node, consider rearranging your setup to connect with ethernet to your main Unifi/Edge router instead. With RoonServer hardwired to the main router via ethernet, you've eliminated WiFi interference with Roon's main connection to the internet.
Verify Line-of-Sight Between Nodes
Nest nodes don't require a clear line-of-sight to connect to one another, but it can help reduce the impact of WiFi interference on Roon. Try placing access points or routers high up, and if possible, try to strategically bypass any metal, cement, or reinforced walls through which a WiFi signal might have to pass.