I haven’t used kagi, but I believe you can do exactly that with it. You do have to pay for the service, but that’s probably a good thing.

This is a link to the features page. It allows you to permanently ban or boost results from specific domains. But you may need to do some manual effort to make that happen, I don’t really know if there are community-curated backbones or anything for that.

But you can also see if the result is popular, and they seem to work pretty hard to make their platform worth the spend. Everything I’ve heard from people who use it is good.

https://blog.kagi.com/kagi-features