"If you’re searching for an air fryer, Amazon already knows quite a bit. They know the best-reviewed, least-returned, best-priced model. The only purpose of the ads is to get you to pick an air fryer that isn’t that one (or for the best air fryer, to keep you on track to buy the one you wanted in the first place)"

I don't get this part. Aren't those things unrelated? The aim of ads is to convince to buy regardless of the quality and other data points.

Yes. Technically, there are situations where the air fryer which is best for you and the air fryer that makes Amazon the most money are the same. However, with the number of airfryers on Amazon it seems safe to assume this is a rare coincidence.