I eventually just scripted a separate search engine query that's site specific to Amazon. It works but not as well as it could because it doesn't have access to my purchase history or Amazon's hidden granular category taxonomy.
It's maddening because Amazon used to have a modern, reasonably capable search function. You could require terms. You could exclude terms. Terms could be phrases. I'm sure they still have all these capabilities, they've just decided to intentionally disable them because their A/B testing indicated that breaking their search would return a fractional percent more revenue by shoveling more unrelated results in front customers. It must work on someone but it's never worked even once on me, because I KNOW what I need and I'm only going to buy exactly that - if I can fucking find it.
I'd actually be okay to let Amazon annoy the NPCs who just clickety-click and buy whatever random shiny shit they shovel in front of them, IF they'd just add something for us technically-minded, engineering type people who are looking for one precise thing only. They can even hide it behind an arcane interface like REGEX. That'll keep the rabble out! :-)
On top of all the other insane choices they made, like removing your search category restrictions if it thinks your query was too precise. I'm close to snapping.
A bit ago I was searching for toothpaste that doesn't have mint in it. This is already a pain at a brick retailer, but I figured Amazon's huge product variety would help. Turns out their search is actively malicious to negative terms because otherwise I could buy just the one thing and be done with my shopping.
I should probably set up a similar homebrew search to get around this. Purchase history is far less important to me because I don't buy much from Amazon.