Isn't Kagi basically just using a blocklist? In which case it's whack a mole as new sites spring up or bubble up to the top of other results. I keep my own blocklist and intermittently search key phrases to blanket block new sites, and there's often new sites popping up.
- whenever a spam site is in my results, click to block
- click through some and check out pages like "About" "Terms" "Disclaimer" "Privacy". often common boilerplate phrases abound. affiliate marketing spam, and similar, for example
- exact string search those phrases
- (get often many pages of results)
- using a userscript, block all domains in each result page
my results have gotten so much better for common types of queries. even then, new sites pop up almost daily it seems. add to the list.
