I was kind of impressed of the precision of the advice given - it perfectly explained various FP patterns used in my code, and correctly concluded that it could not be refactored to be better/simpler/more generic, but suggested some good readability renamings. My general worry is that AI tools will hallucinate and/or just provide random or sub-optimal/average solutions.

Do you mean Live Share with an AI, or just as a feature for pair programming with humans? Doesn't video conferencing tools work well enough for that?