It's open source, no need to sell ;)

Some video that will probably be more digestible

What's underneath

I'm not sure from what POV you are coming, so first of all: Logseq allows you to write notes in markdown format (I don't know how canvas' work but it also should be some open standard. SVG maybe?). It is versatile while still being readable in pure text format. It also means that those are mostly pure files, so you can back them up however you want, you can move them to another markdown editor, another notes management program, etc.

Tags and references

Now, let's say that after an adventure you want to have some news for your players. I would go about it this way:

• create a note containing only the text of the news
  • tag it (file property) with news, radio #1, maybe a reference to the parent adventure? Depends how you will want to view it in the future
• in the adventure put header [[post mortem]], so it also is a reference to post mortem note (does not need to exist ATM)
  • underneath put header [[news]], so news tag/page (Logseq does not really differentiate between tags and links) will also get a reference to this adventure.
    • udnerneath embed our note with a TODO/DONE, so you can mark if you passed it to them already

That way, after a bunch of adventures

1. you can open post mortem page and see all references from all the adventures
2. you can open news page and see a list of all pages tagged with news
   • you can also put in some query to group them, but we'll get back to that later
3. you can open radio #1 and see all the news they said
   • and add some general notes about it, directly in that file. With links to background notes
4. you can open an adventure and read the whole write-up from the conception to post mortem (if you organized it that way. I could see someone splitting those up again into separate notes)
5. you can open a news note and see in which adventure it's referenced
   • if you used some tags/links in the note itself, you can also, in the note for big bad, see in which notes they were referenced

Summary notes and tag structure

Let's say you have a bunch of adventures, some tagged as adventure some as adventure/done. Logseq will recognize the latter as a part of a structure, same as if those were directories. But since everything is a note, you can have a adventure note that is like a summary for all the adventures (you will get a list of all references out of the box). Or a note act 1/adventures with only the adventures in that act (and background tags structure shared between them). With queries, you can in any note get a list of for example all notes that are act 1, and not tagged with adventure/done. So you still can have hierarchies where it makes sense, but you are not locked out of some name for a note because there is a directory with that name (like Obsidian does and why I decided to phase out of it). BTW, you can also embed only one point from another page. So you can take a reference to a point in the plan for an adventure from the past, embed it in another note, and if you decide to add some info to it, editing it in the embedding note will also affect all the other occurrences of that point

TL;DR

So in general it's very versatile, very tag-based, while not locking you out of directory-like structures and based on pure-text files (you can embed images) that are readable by other tools too