All mapping your own genres to Roon defined genres does is to add them as albums under the mapped Roon genre.
So when you Focus on the Club/Dance genre it will also show your albums with the Dance tag (but that don’t have the Club/Dance tag).
I’m in the process of removing the Pop/Rock genre completely from Roon, creating a new top-level Rock genre. And like you only see my library, no ‘Recommended albums/artists’ or ‘New releases for you’.
I’d suggest editing your topic title and move the topic to the Feature request section.
(just in case you didn’t know - you can click the pen icon next to the title, to edit/move)