In my use, docling has not involved an LLM. There are a few choices for OCR, but I don't think a vision model is one of them.
It's certainly touted as a solution to digest documents into plain text for LLM use, but (unless I just haven't run into that part of it) it does not employe an LLM for its functions.
docling uses an LLM IIRC, so that's already a difference in approach