Specify genre for iTunes Radio
The top-right corner of iTunes has a search box. Typing in "mongol" gives "Search for "mongol" in Apple Music". That gives "Showing Results for "mongol" in Apple Music".

Listed amongst that is "Top Results", "Albums", "Songs", "Artists" and "Stations". Stations lists radios such as "Mongol Radio".

Seems a rather roundabout approach, but at least it works.