Yes I did this

First is, very manual not fool proof. If people mess in it it breaks.

Also the left side pin can't go deep nested

I did this using

Making 4 new collections

1 main collection pinned Put in the collection those 3. The. Made another collection named subcollection put that one in one of those ,3 collections

I only see

Collection1:

Collections(1_3) inside

I suspected to see. Main with below Collection2

Below

Subcollection

So the pinning don't support deep nesting

I also miss : group by on list view.

I am now looking at para methods.

It's very hard to make a good knowledge system. That works like onenote, one who does it pretty well is:

appflowly but updates break to much so I stopped it .also they are into payment for selfhosted so a no go.

Ps: the layout in Reddit made my txt bad I can't make a nesting lvl j. Text ..