GPT3 is certainly a valid thing to consider, but I think it has some weaknesses (e.g. there's an uncanny valley to them in terms of balance between relevance, novelty and coherence) and even the most sophisticated GPT3 cannot, by itself, mess with every marker (e.g. volume, distribution of content quality, conflict of interest between having generated low reviews and the ability to doctor review numbers, nuances associated with weasel words in real text vs in training set, variance in emotions/tone/interjections, reviewer consistency, aggregator reputation, etc)