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)
Have you confirmed that no website you provide ad revenue or membership fees to used AWS? If you haven’t checked, then you probably have supported Amazon. Amazon makes most of their money through AWS.
Regardless, good on you for not buying from Amazon directly. I too haven’t purchased from them for years