The GPT-3 you had access to when it was free is quite different than what’s deployed today, and its ability to handle long-form inputs is its most apparent change. I’ve gotten it to give good summaries of ~5000 character texts but I admit I haven’t gone longer than the context length.
Edit: Here’s an example summarizing 8,294 characters of Harry Potter fan-fiction: https://twitter.com/goodside/status/1561213457374011392?s=21...