I mean I have asked LLMs about the SAME things in our legacy codebase probably 50 times now, (because I always forget, and that I don't understand much of it). And I have yet to get a perfect summary, a perfect diagram of overall concerns.

Its still much better than trawling thrugh code yourself, but they are far from all-knowing. I have to say they have gotten 10x better in just a year as well. Or they are very good bullshitters and just sound confident.