The Roon team would love to have more options than Tidal integrated into the program. Roon will work with Apple if hey let them. Make the suggestion to Apple.
I couldn’t see my iTunes playlists until I “checked” the show shared playlists button - then they showed up.
Perhaps ROON should ask Sonos, how it works to get a deal with Apple 
Don’t call them – they’ll call you.
Or not. Most probably.
Ok, perhaps you should call Deezer (Elite)