Hi there! I am extremely glad to read someone else write about this necessity!
I own and operate a "list-taking" app[0] in which every list/kanban-item can itself be a list/kanban.
I currently use it for things I'm the creator of -- tasks, story outlines, etc, but looking to introduce 3rd party content for task management (I want to see GitHub tasks from work next to my own tasks) and, as you say, knowledge management of things like recipes or music.
Items could be part of one or multiple hierarchies. A list of "cake" recipes could be under both "baking" and "party essentials", and music playlists could include other playlists.
As you can tell, this can become convoluted in my mind, and so if that's something that's interesting to you (or anyone reading this), please reach out and let's discuss! hn at nestful.app
[0] https://nestful.app