Unless you have the privilege of being an enterprise customer with an SLA guaranteeing privacy, there's not much you can do other than using local models. I believe OpenAI says they don't train based on API requests but that's more of a "trust me bro" than any kind of guarantee.
Team and Enterprise come with the non-training guarantee, free and premium do not. Pretty much anyone can sign up for Team (I have, and I'm not a company) but you need to buy at least 2 seats for a total of $50/m. The rate limits are much better with that as well though.
