Cancelled my Prime subscription last month after the past year of worsening experiences with Amazon:

Received several orders that were returned items, with broken open packaging and sometimes the item was something else entirely, purely put there for weight by whoever returned it.

When I went to return some things at a major Amazon distribution center, the return area was closed for the week for some sort of construction or renovation, with no indication of that anywhere on the site. The only messaging was a piece of paper in the window once you got there.

At another separate major distribution center, the return area was a small room with pieces of paper taped to a door with an arrow pointing to the Amazon lockers where the returns are accepted.

Orders are now often so delayed that it makes the Prime subscription pointless. Have had multiple orders over the past year that didn't ship for 3 or 4 days.

Amazon listings are almost half Sponsored listings now, and there are unrelated ads on the side of listings.

Half of the listings are some random made-up brand name, like XIJGNU, which is just a Chinese seller selling low-quality products, and when the reviews get bad enough, they re-list the product under another made-up brand name.

Fake reviews were already rampant before LLMs, but now reviews are effectively useless because they are so easy to fake.