I thought the problem with that was even if you chose to "buy" a product from Amazon, if a 3rd party seller is using Amazon's warehousing, Amazon intermingles products that they source themselves and from the 3rd party? So, you could be getting a product sourced by Amazon, or you could be getting a product sourced by a 3rd party.

They definitely removed it years ago, at least for me. The option to check mark “Amazon.com” as the seller was there and then it wasn’t over and over, and then eventually just disappeared.

Edit: I just searched shelf and hot sauce on Amazon.Com on iOS Safari, and the filter options do not show any way to restrict to items sold by Amazon.com.