An alternative LaTeX plugin for TiddlyWiki5. It supports a wider set of LaTeX commands than KaTeX, though not as extensive as MathJax
http://tw5-texzilla.tiddlyspot.com
This plugin provides LaTeX support in TiddlyWiki5, using the TeXZilla latex parser to generate MathML.
Only Firefox and Safari support MathML at the moment, so the plugin is only useful if you're using one of these browsers. It might be possible to combine this plugin with MathJax to convert MathML to something that other browsers can understand, e.g. HTML+CSS, but I haven't tried this.