From your sibling comment, https://tosdr.org/ seems like it gets partly there. The items listed don't seem to be standardized for the initial view though. Then again, I just visited it for the first time in years (I had heard of it, but completely forgotten), so I don't claim to have a good idea of exactly what it offers.
The first step would be getting a formalized set of metrics, which is in itself a bit project. Once you have that, a framework to crowd source the specific answers from users (hopefully with references to a TOS/Privacy policy section) would be the easiest way to keep it up to date. Allowing comments and annotations for further info on a specific company's rating for an item that could be expanded would let people drill down on the details.
The first step would be getting a formalized set of metrics, which is in itself a bit project. Once you have that, a framework to crowd source the specific answers from users (hopefully with references to a TOS/Privacy policy section) would be the easiest way to keep it up to date. Allowing comments and annotations for further info on a specific company's rating for an item that could be expanded would let people drill down on the details.