I just gave it a try. For me, Roots Magic 7 launches (I see "Roots Magic" in the menu bar, but then, nothing. If I hover over the menu bar I see a spinning rainbow. The application shows "Not responding" in Activity Monitor. After ten minutes or so, I force quit.
I installed Catalina from the first release and have been without RM since (except for viewing data on my iPad). I'm up to date on Catalina, running on a new MacBook Air. I will give it a try in a test user where I don't have a zillion things running in the background, but clearly it doesn't work in my normal configuration.