Passmark's site has been my go-to for at-a-glance comparisons of GPU and CPU for a while. It just lays out specs and performance on a common benchmarking suite.

Looks like 6950XT has similar performance and favorable value compared to similarly-priced recent-gen cards.

Unfortunately, I don't know of one. It may just be best to look at individual reviews.

You should look up some of the controversy with userbenchmark. The owner is a competitive shooter player so he favors single thread performance over basically everything. When he got called out by some big tech channels he had a tantrum and made pages on the site dedicated to trying to talk shit about them, linked right in the about page.

It's actually really funny.