This is just a basis for further refinement. Flarum allows primary tags with a 2-level nesting which act basically like folders/forums. Addionally secondary tags can be added on top and act more like classic tags, i.e. more than one can bee added to each thread.
My thinking was to create a primary structure by the kind of information posted and use secondary tags to further clarify the topics talked about. As these topics often can't be clearly separated, tags are a great way to put things into multiple drawers.
Happy to hear suggested improvements.