For others, this is a sub optimal answer, but I’ve played with generating grammars with latest llms and they are surprisingly good at doing this (in a few shots).
That being said, if you’re doing something more serious than syntax highlighting or shipping it in a product, you’ll want to spend more time on it.
Uhh… The fact that there's no Archlinux package for a given language doesn't imply there's no tree-sitter support (official or 3rd-party) for that language? See e.g. the very long list of languages on https://github.com/Goldziher/tree-sitter-language-pack , which does include R, YAML, Golang, and many more.