After a lot of consternation, I came to the conclusion that investing effort in a bespoke note-taking application was not worth my time, and returned back to Obsidian. There were a few considerations that persuaded me.
Firstly, I found that while editing, having access to the interlinked document view was very essential. It would have required a lot of work to implement this, and my ideas of editing things purely in the terminal, relying on the blog generation tool to visualize my work would not be sufficient.
Secondly, the ease of creating new notes and linking them really is that much better in a mature tool like this. In my own bespoke tool, it was a real impediment to writing to have to manually create new notes, while here, everything is always a couple square brackets away.
Finally, there seems to be considerable momentum behind Obsidian, which means that tooling around it, for editing, visualizing, and publishing my graph will improve over time, without needing additional effort on my part.