Nah.

I read like 5 or 10 and try to see the common pattern.

No. I consider reviews and review sites to be basically worthless and pay no attention to them. If I'm making a nontrivial purchase decision, I research the product itself first (not reviews of the product). The closest I get to paying attention to "reviews" is that I do a web search looking for people asking for help resolving issues with the product. That gives me a good idea of how problematic the product is and how much difficulty people have had engaging with the manufacturer about problems.

> Would you trust an app/extension that automatically aggregates the best products across multiple reputable review sites, shows you the sources, and ranks them by how consistently they’re recommended?

This is unlikely to be of interest to me. How would just a site define "best product", how would it decide what review sites are "reputable", etc.? Also, review aggregators like this historically have been even worse than the review sites themselves.