I came up with a new approach: by patching rapydscript-ng (a tool that transpiles Python-like syntax to JS), I make it translate Manim code into JS, and pair it with a companion JS library. This lets it run the original code in a small enough bundle.

Fortunately, after overcoming some difficulties, it worked! It runs surprisingly well. You can see a blog I built here: https://wanim.org/blog , or try running your own Manim animations at https://wanim.org/playground.