Do we? When have LLMs come up with heuristics? I'm sure if you ask an LLM to tell you e.g. how to solve a maze it will print out the instructions for the follow-the-left-wall heuristic, but that's not "coming up" with a heuristic.
I fear though we are about to go into one of those unproductive conversations about the capabilities of LLMs to produce novel results which I think has now reached saturation point all over the internets.