I’m increasingly hopeful that we’ll get native AirPlay 2 sender support when Roon runs on a Mac. The reason being that the latest Roon release (2.0.5) treats Roon running on Windows specially, so this sets a precedence for treating Macs specially, too, as requested in this thread.
(for reference, from the Roon 2.0.5 release notes: “Roon running on the Windows platform now fully supports the native media transport controls …”)