Roon radio has been reported before as being pretty rubbish when it comes to EDM (progressive trance in this instance)
The radio gets a number of inputs, but a big one is “what did other people play” and I don’t think a lot of people play this compared to rock/pop/jazz etc so the pathways aren’t there.
The users in this thread may have opinions
My tastes are more roon mainstream so radio works well for me most of the time.