Obsidian is a great Tool, its one of my choices to create the Wiki, but is paid for use online. But the one file aproach of Tiddlywiki and the personalization is great.As a side note, if you have the RTF versions of the books from the Core rules, Obsidian is an excellent bit of kit to paste the text into (in small sections, by subject) and hyperlink. I believe it has tools for making the data available via cloud/web, but I haven't tried it. It also has a database function, so with some work I bet you could get it to handle character creation and even have hyperlinks on the character sheet back to the appropriate expanded information from the rulebooks - a mini D&D Beyond for 2E, if you will.
I had an old Wiki for my homebrew world and pulled it into Obsidian and it respected the hyperlinks there, so it will probably work with Tiddlywiki too (Obsidian may even have some extensions specific to working with Tiddlywiki).
It's possible to link and transclude the text inside Tiddlywiki, take a look at the Baatezu >> Demônio das Profundezas, and look at the Descrição (Description) tab, or Combate (Combat) tab, all spells he uses are linked and open in a separate tiddle (card information).
Its Very fast and organize the rules in a non linear way, or maybe i just a proud father hahaha.