To me, it feels like the subcategory list is an extension of the categories with featured topics layout. I know I’m in the minority using categories as my home page rather than latest though. For example, if you go to my home page https://community.naturephotographers.network/ and then go to Image Galleries, it’s a natural progression of hierarchy.
If the category is intended to be hidden it should be hidden on categories with featured topics as well, but it has to be more clear in the description of muted that this will happen since it will not be easy to get back to the category then. There almost needs to be a tracking option of ‘hidden’ for categories to hide it everywhere, not that I want another option to confuse users, but just throwing out ideas.