MathML Core is a subset with increased implementation details based on rules from LaTeX and the Open Font Format. It is tailored for browsers and designed specifically to work well with other web standards including HTML, CSS, DOM, JavaScript.
I don't have a lot of experience working with this stuff (yet) but if you can script your MathML objects with Javascript, you should be able to make whatever interactive "stuff" you want in terms of math notation.
Now drawing objects and plots and stuff is a different question. There's stuff like Plotly.js[2], D3.js[3], Sigma.js[4], Three.js[5], Two.js[6], Paper.js[7], etc. that might be useful depending on exactly what effects you're going for.
[1]: https://developer.mozilla.org/en-US/docs/Web/MathML
[2]: https://github.com/plotly/plotly.js
[3]: https://d3js.org/
[5]: https://threejs.org/
[6]: https://two.js.org/
[7]: http://paperjs.org/
Manim is a python library, Motion Canvas is Typescript and uses Canvas