At risk of throwing the baby out with the bathwater, think back to how you would've browsed the internet before Google. You probably would've grown your own web-directory of bookmarks, right? That's also how you explore the non-SEO-paved parts of the internet now.

I haven't learned to find product reviews yet, but I imagine that a trick would be to know which forums to go for certain kinds of products, e.g. maybe https://xdaforums.com/ for Android devices.

There is also the search engine https://boardreader.com/ which ONLY searches proper forums--sometimes you find neat threads, sometimes not.