That's it. I'm turning off the lights and closing up. Tiddlywiki is being shelved. Until such time that Felix returns, if he ever does.
In the meantime, anyone who's interested in a maintained graph visualization plugin for tiddlywiki, I invite you to check out TW5-Graph. It's heavily inspired by TiddlyMap, but aims to be more hackable, lightweight, and not reliant on Vis-Network. Most importantly, it's not only actively maintained as of right now, it's being actively developed. New features are still coming in.
Felix, if you're reading this, this is your project, and you're absolutely free to bring TiddlyMap out of Legacy, but I'd also invite you to check out TW5-Graph. It's heavily inspired by your work here.