Man, I love Kagi. Two years ago I would never have thought I'd ever pay for a search engine, but the option to block garbage domains like userbenchmark or sites with purely AI generated content is just too good.
Yeah the best feature. Also filters those results from your assistant queries so less slop contaminating your results.
For what it worth, there's uBlacklist for Google.
https://ublacklist.github.io/docs/getting-started