Although I know you said this in jest, it got me thinking that it would be really fun to have a system where you have to submit answers to a short quiz about the book before you can submit your review. No reviews would be removed, but you would, if you wanted, be able to filter the global average by people who scored over a certain threshold on the quiz.

Probably you could even generate new questions every time with GPT, so that people couldn't cheat. This system would have a million problems, sure, but would it have more problems than the current system?