I feel like amazon just appends the values you select on the left sidebar to your search. There's no way they're actually properties of the listings in any way.

Give me search like McMaster-Carr. Everything is an instance of a category class with madatory properties. If your product doesn't fit in any existing category, tough shit. Go convince someone at McBezos-Carr that whatever premade-landfill product you're selling is a category, along with providing dimensions/materials/properties that category varies by, and maybe they'll consider adding it.