> I see, so in your opinion having a central engine won't be a bad
> architecture design for Emacs despite major modes having their own engine.

On the contrary: moving indentation to tree-sitter would be of great benefit.

> I wonder: is possible for any other package to "take the wheel" from major
> modes when it comes to indentation

I think it's a simple matter of

    (setq-local indent-line-function #'tree-sitter-indent-line)


-- Stefan