It's even listed on the "official" MLS implementations page, great process on the PR /s, and the author of that ts lib opened a pull request for it despite writing in the readme:

This library has not undergone a formal security audit. While care has been taken to implement the MLS protocol correctly and securely, it may contain undiscovered vulnerabilities. If you plan to use this library in a production or security-critical context, proceed with caution and consider conducting an independent security review.

Make of that what you will. If I personally were to integrate a standard and there would be no audited, non-solo developed libs, I'd probably write and have audited my own lib. So in either case we're kind of back to "you're right to fear it", sorry, lol.

However: that implementation still isn't the hardest problem. The hardest problem, even if you write a ts mls lib yourself, is still key management.