Apropos "[...] for Everything", https://github.com/kisonecat/tikzjax might be of interest. It uses a WebAssembly copy of tex.

Regrettably neither KaTeX nor MathJax support category theory diagrams. And I'd like to try making interactive diagrams, to explore using mouseover supplements to reduce the learner cognitive burden of keeping track of all the moving pieces and their significance. Perhaps they might be combined with a generic js diagram library... but it doesn't look like anyone has bushwacked that path.