Adding Child Blueprints to packaged game as DLC, Game Features or UGC?

I’m basically looking to add child blueprints after a game has already been packaged. Should I be looking at UGC or Game Features?

I have a grid menu with tiles, each child blueprint registers a tile, I want to be able to add and remove these tiles as DLC packs. Not sure if Game Features can have any pre existing dependencies? That would probably defeat the self-contained purpose