I don't know, unfortunately. This reminded me that I used to occasionally read product reviews on epinions.com, which was apparently was taken offline in 2018. It was basically what you're describing. Another proprietary website bites the dust and loses all content. :(
I heard about neodb.social recently, which is for entertainment media and is popular in China (although you can post in any language). Seems like we need something like that, but without specific product types in mind.