In case it helps, I've run into the same types of problems frequently, and YouTube reviews are a godsend.

Random people actually film themselves unboxing and using the product, and you can watch what buttons they have to press, etc.

Also you can virtually always download the manual as a PDF.

Of course that's not a list, and it takes a lot of work. It's deeply unfortunate -- somebody like Amazon could actually implement the kind of comparison matrix you're talking about, but they're not exactly innovating on the UX front. :(

(Amazon does sometimes show a comparison matrix of 4 products with something like ~6 rows of features for some products, but I think it's created by the manufacturer, so only compares models for that one brand, and doesn't always list the feature you care about either.)