As long as I cannot access their data, cannot see their systems on a continuous basis, they can collect my data. The same applies to DuckDuckGo and the same applies to VPN services.
So at Kagi they are aware of Tor, they are aware of the Dark Web. If you even talk about this on your website, of course you find ways to circumvent privacy there.
I tested Kagi and my experience is the results are even with or worse than what other services present like Google or Bing or even Perplexity. And if you don't like advertising, just use an ad blocker. I'm so surprised that so many people don't seem to do this and they always complain about ads. Just use an ad blocker already.
So they allow me to modify my own website ranking. Well, if almost nobody uses this website, that's pointless. Besides, if I could modify my website ranking, so can everybody else. And now we are back to search engine optimization.