I finally found a bit of time for neocaml (https://github.com/bbatsov/neocaml) - my attempt to create a solid modern #OCaml major mode for #Emacs, powered by #TreeSitter. In case you're wondering - I've named it "neocaml", because there were already a couple of "ocaml-ts-mode" projects out there, and I like fun names.
The core functionality is more or less ready, so if someone is interested in playing with it, they are welcome to do so.