I have a screenshot from 2024 when I asked ChatGPT to write me a draft of a story about a young boy who lost his parents and got send to a wizardry school. I specifically asked for the story to be original and not based on anything that has been already published.

As you probably suspect, chat gave me a full synopsis of Harry Potter.

I kept asking if that's an original idea, and it kept swearing on it's mothers grave, that the story has never been published before.