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.
Haven't looked for this before now, but this seems to be supported by DuckDuckGo as well. Search result three dots > block this site from all results.
It rarely survives closing and reopening Safari on iOS (without clearing cookies), so it's not as valuable.
If you go to duckduckgo.com/settings you can generate a URL with all of your saved settings. Loading it will configure all the settings it includes in your browser's local data. Blocked sites are included, I just checked.
It always takes me awhile to remember where this setting is buried in their menu. In case it helps someone else: https://kagi.com/settings/user_ranked . Besides blocking, they have ranking adjustment options on this page as well.
Yeah the best feature. Also filters those results from your assistant queries so less slop contaminating your results.