I can't speak for every implementation, but in the one I use (logseq) if you say back-link 'Podcasts' in 'Audiodrama' then in 'Audiodrama' 'Podcasts' will show

I can't speak for every implementation, but in the one I use (logseq) if you say back-link 'Podcasts' in 'Audiodrama' then in 'Audiodrama' 'Podcasts' will show up as a 'linked reference' like so (https://imgur.com/5FADCI5 https://imgur.com/5FADCI5), as well as a bi-directional connection in the graph you can get of all your links. Over time this produces something like this (https://imgur.com/6I9ojRG https://imgur.com/6I9ojRG), which is what I meant by self-organizing. Just with back-links without having to create any hierarchies (what i meant by unstructured) you get a data-structure that is actually still pretty insightful.