Who’s better? By how much? Why?
I’d still be interested in knowing if a resource like this exists, though.

I'm not sure about "progressively trickier", but otherwise two books have what you are asking for. The first is "Strategic Chess Exercises" by Emmanuel Bricard and "Test Your Chess Skills" by Sarhan and Logman Guliev. In both books, you are given positions and asked to evaluate them and sometimes to find the right continuation. The solutions are detailed explanations.
In the same vein is "Chess Exam and Training Guide" by Igor Khmelnitsky. This book follows the same pattern of positions that you have to evaluate, followed by detailed discussions. It differs in that it allows you to grade yourself on 12 different aspects of the game.
None of those books are easy. They all take a lot of work, sometimes quite frustrating. The great value of the Khmelnitsky book is that your grades in the various areas will point out your most significant weaknesses so you can work on them first.
Best of luck in all your chess endeavors.