Prime Day? More like Same-As-the-Rest-of-the-Time Day. It has always been a highly-hyped disappointment of a store-wide sale, and this is not news to anyone except people who have never before shopped on Amazon's web store.
I have never found anything even close to a good deal on Prime Day, and it has been several years since I even bothered to check prices.
You're better off marking a product you might like to buy, checking its price history on another site, and possibly setting an alert to notify you when the price drops below a threshold on a third site. If that alert happens to go off on Prime Day, you got very, very lucky that it somehow managed to be chosen as a loss leader.