There’s already a “typed too fast” detector that should catch cut & paste?
As for analysing the actual content, I’ll just leave this right here:
" As of July 20, 2023, the AI classifier is no longer available due to its low rate of accuracy. We are working to incorporate feedback and are currently researching more effective provenance techniques for text, and have made a commitment to develop and deploy mechanisms that enable users to understand if audio or visual content is AI-generated."
I’m not aware of any replacement.
This is a hard problem.