Unless you personally developed the AI to do this, then it is almost certain that any third party AI is harvesting every nugget from you in one way or another. Even when they say they aren't. Like all the other big tech out there, it was designed for the makers not for the users.
This thread is about a locally running LLM, with an air gap.
How can a third party company harvest anything from that? Even if you didn't develop the LLM yourself, if you downloaded it and are running it locally with no internet access, I don't see how it'll leak info to a third party.
What if there's no typed or visible text, and the entire chat is done via audio?