After a conversation on irc.social.lol and some thought, I decided that TiddlyWiki isn't the right tool for me. My note-taking style just doesn't fit it.

I like Notesnook and its rich-text editor, but my note-taking style doesn't fit it either.

So I switched back to Standard Notes. They've fixed the bug that broke third-party editors, so I can use Rich Markdown Editor again. I write and edit my notes with Markdown styling in plain text, then switch to RME for a preview.