I just set up at a new location where currently I don’t have cabling between where fiber ONT is downstairs and where I have the first Roon wired endpoint upstairs. I may still get it all wired, but in the meanwhile I installed a UniFi Dream Machine (which runs the UniFi controller) wired to the ONT, the Roon core (fanless Zbox CI662 nano with Ubuntu Server 20.04.1, 4TB SSD) wired to the Dream Machine, a UniFi FlexHD upstairs, powered by the included PoE adapter, and Cat 6 to a dumb switch for all the wired gear in the room including the Roon endpoint. Setting up everything was a bit tricky as I don’t have much cell service here and yet the UniFi Android app need to talk to the mothership to create an account etc. But once that hurdle was overcome (holding my phone high up by a window) and I found my way around the mobile app and the Web controller interface, setting up the network with wireless backhaul between the FlexHD and the Dream Machine was really easy. This neighborhood has very little WiFi interference, so it may be ideal for this setup. Playing both local music and Qobuz with no issues so far.
At my other location I have an older Ubiquiti EdgeRouter 5 with a MoCA coax Ethernet LAN and AmpliFi HD mesh for remotes.