Strike that off the plan. Thanks.
I just relaunched hqplayer on Mac, denyed connections out until quit with littlesnitch to signalyst.com and signalyst.eu
It did find my naa and allowed me to play local files. So I guess it does work. The iOS app doesn’t seem to work though.
So it’s kind of a fallback solution. It works better than Roon does without an internet connectivity.