It's unlikely that we would include that in core lite-xl due to size and complexity, but we aim to have an extremely robust plugin system (all current syntax definitions come from plugins).
It is totally possible to integrate an lpeg and scintilla plugin which could drop in replace the existing syntax support.
We already have a community member doing this, but with TreeSitter, though I'm not sure where that effort is at, at the moment.
If remember correctly, the [Howl editor](https://howl.io/about.html) has Lpeg and use of scintillua. It looks great and it's older but I'm not sure why Lite got more press coverage.
https://github.com/orbitalquark/scintillua
Which would give fairly complete syntax coverage, and a good foundation for building more sophisticated tools.
Lua patterns are fairly primitive, while the opposite is true of Lpeg.