Looks like they've made it more complicated

I went into Amazon and clicked on a product randomly then scrolled down quite a but to find the 'star' section (customer reviews).
If you click on
Learn more how customers reviews work on Amazon it says
How we calculate overall star ratingsAmazon calculates a product's star rating using machine-learned models instead of a simple average.
These models consider factors such as how recent the rating or review is, and verified purchase status. They use multiple criteria that establish the authenticity of the feedback. The system continues to learn and improve over time.
We do not consider customer ratings without an Amazon-Verified Purchase status in a product's overall star rating until a customer adds more details in the form of text, image, or video.
Not sure if this helps but there's lots more in that section
