Aliexpress just fake it themselves. Search for anything, sort by the number of orders, open the product page for the first result.

Next to the number of sales there's going to be a tooltip saying "Sales and ratings are calculated based on all identical products from the platform."

Under reviews there's going to be a message saying "The reviews displayed are from various sellers for similar product in AliExpress."

In other words, they might as well say that these numbers and reviews have absolutely no relation to the specific product you're thinking about buying, they're just there to increase your confidence.