Kagi charges a subscription and does not sell ads against your queries. Lenses let you tilt results toward sites you trust and away from farms. The company is in the United States. You are the customer, which is the actual privacy claim: they do not need a dossier to sell to someone else.
Paying does not make the index magic. Kagi still has to get pages from somewhere, including its own crawler and other sources, and a paid account is an identity if you sign up with your real email. The free trial is the right test. If the results are worse for the work you do, the philosophy does not matter.
Use it if you search all day and hate the ads. Skip it if you will not pay. kagi.com
Kagi’s lenses and the ability to pin or block a domain are the reason people pay. The trial will show if that fixes your actual queries. A subscription tied to your email is an account. Use an alias if the searches are sensitive and you still want the paid index. The company can see queries. They are not supposed to sell them.