Default unspecifically-prompted AI writing makes you vomit, because it has a specific pattern.

But with enough well-defined prompts AI can be made to write in practically any style, often with results unrecognizable as AI-generated.

It does not matter which prompt you use. Even a long article with a small input (of what to write) will include weird details and structure.

People tried to fool Pangram by using custom prompts and instant feedback (rewrite until it passes). After hundreds of rounds, the text was still detected.

Although it's harder to detect such text by humans, there will be clues if you want to write a whole book based on a few pages of input.

Show me. AIvangelists love to say what AI can do, but never bother to provide any examples.