I find, across the board, Amazon often feels like their incentives don't align with those of a customer.
They're always trying to push Prime (and to a lesser extent their video and music service) which represents extra clicks to sale. It's a significant auto-renewing commitment, not a $5 casual impulse add-on-- repeatedly dangling it in front of me and hoping I misclick into it borders on a dark pattern. I'd love to see a big one-click "I am not interested do not bother me further" button.
Everything about their checkout funnel is contrary to modern best practices. Fields are oddly arranged compared with most other ecommerce sites, and once you reach a certain point, the normal navigation disappears. I guess this is designed to trap the user with no way out but purchase, but it makes it harder to compare items, especially when you're trying to find out on shipping (see below).
Shipping is a mess to deal with. "You need to spend $25 for free shipping, but these items don't count". "These items can ONLY be purchased with an order of other items that hit the free-shipping threshold." "These items can only be purchased with Prime." There's no easy "estimate shipping" button without going several pages into checkout. These sort of complexities probably are engineered to steer customers towards buying the items fulfilled by them to avoid the pitfalls.
I'd also wonder if their brands "accidentally" do well because of how bad their product categorization is. Nobody else is selling AmazonBasics products, so the single listing gets all the ratings and sales volume. Meanwhile, the name brand has 30 slightly different poorly arranged listings all overlapped.