I came to this subforum looking for help for pretty much the same problem, but I “only” have 500 reviews. 
I’ve been trying to bring them down for a while now but I don’t log in every day and they keep piling up. I’m pretty much trying to say you’re not alone in your steaming pile of reviews.
I use the flaming durtles/smouldering durtles app and, while the app is really great and much more useful for daily use, I find that sitting down at my PC and grinding many reviews is much easier on the website than on the app. YMMV.