> This has been the secret in my experience. Pay for Prime, and only buy Prime items. For me the convenience is worth it, even though I know I’m feeding directly into what Amazon wants; to not fix their massive counterfeit problem.

That won't really help. There are prime-eligible counterfeits shipped from Amazon's warehouses due to the Fulfilled by Amazon program. Even buying from a known trustworthy seller is not enough, as Amazon commingles FBA/Prime-eligible inventory from multiple sellers of the same item:

https://www.wsj.com/articles/on-amazon-pooled-merchandise-op...