The key is 100% boycotting all services provided by a company. Wikipedia’s list of Amazon product/services as reference (https://en.wikipedia.org/wiki/List_of_Amazon_products_and_services).
Incidentally, I know entire neighborhoods that don’t have other grocery stores besides Target/Whole Foods, not to mention that AWS is the cloud computing industry standard… As a personal example, my vet-prescribed cat foods are manufactured by Purina, a subsidary of Nestlé (needless to say, a separate but also extremely evil large corporation)
It’s more realistic when the boycotters have a specific demand, e.g. getting the company to divest from Israel.
Then the boycott just has to do them more damage than quitting Israel would.