Parsoid[1] is what you'd want for that, most likely. It's the new wikitext parser that MediaWiki is gradually switching over to, but it has the virtue of being usable entirely outside of MediaWiki if you need to.

[1]: https://www.mediawiki.org/wiki/Parsoid

Yes, but it implements lua by calling into the old stack, which doesn't really solve OPs problem.

Okay, yeah, I guess that Lua modules in particular are going to make everything fall down.