You're obviously a good writer. I can tell that just from reading this essay. I'm sorry you've had such a poor experience with KDP, and I don't have any answers. I wrote a book that I didn't expect to sell tons of because it's for a niche market. Still, I expected it to sell much better than it did. I promoted the hell out of it, and sent advance review copies to many people in my network. Then I followed up with them. I probably bugged many of them until they gave up and reviewed it to shut me up. That much worked. We ended up with 180 reviews, which I think is pretty good for such a niche publication. But even that didn't really help. I joke that I have more reviews than sales, which is an exaggeration but also isn't terribly far from the truth. Keep writing. That's my only advice. You have a strong voice that should be heard.