Amazon is absolutely terrible. Try this search, for example: https://www.amazon.com/s?k=A1990+trackpad+replacement

There is an actual product (https://www.amazon.com/gp/product/B084GKQB9T) with all of my keywords in the title. I found it via a google search because I gave up scrolling through Amazon.

I actively avoid shopping Amazon where possible these days, just because it's such a trashy experience.