Read a bunch of books not present in the training data on a specific topic, and learn something from it.

You can cheat with tooling like RAG or agentic frameworks, but the result isn't going to be good and it's not the AI that learns.

But besides this fundamental limitation, had you tried implementing production ready stuff with LLM, you'd have discovered that language models are still painfully unreliable even for the tasks they are supposed to be good at: they will still hallucinate when summarizing, fail to adhere to the prompt, add paragraphs in English at random when working in French, edit unrelated parts of the code you ask it to edit, etc, etc.

You can work around many of those once you've identified it, but that still counts as a fail in a response to your question.