I’ve always had difficulties organising information so that it reflects how I see it in my mind’s eye. A conventional filesystem tree structure just doesn’t work.
I like each unit of information to be stored as a Xournal file, containing both text and graphics -but this forces me to trawl through lists of filenames, which isn’t the kind of fluid retrieval process I’m aiming for.
Instead, I create a very small number of LibreOffice Impress slides and make some kind of meaningful 2-D collection of headings on each. These headings can themselves form a diagram showing relationships between units. Each heading has a hyperlink to a Xournal document. Clicking one allows that unit to be immediately opened and edited on the screen of my tablet.