I have an idea (reach out to me for clarification if you wish) to use conditional surveys for reviews and I think I have a way to do it, but it's a little clunky.
Essentially send conditional survey, then once they get to a spot you ask them how they'd review the service 1-5 and use the conditional formatting to disqualify 1-4 (maybe even ask what could be done to make it a 5) and anyone who selects 5 is prompted to leave a review.
I believe I can do it with a trigger, but it would send out an email, text or whatever and I think it'd be so much easier and smoother if you can put a url to the review page on the survey itself.
There may be a better way beyond that, but that was my idea right off hand to ensure higher reviews.