Hi @Mediahound,
Thanks for writing to us about this issue. Unfortunately we do not support the use of private relay on servers.
MacOS Monterey
With the release of MacOS Monterey, MacOS has a new feature called Private Relay. Private Relay works in a similar fashion to a VPN and can sometimes cause Audio Outputs to not show up properly in Roon. If you are making use of Private Relay, please be sure to disable it when using Roon.