... Okay, I just tried Stract, and its results are... Mostly not helpful.
My understanding is that Kagi makes an effort to tell you how they anonymize your search so they can't tie it back to your account afterwards, whereas Searx is more dependent solely on the goodwill of whoever is hosting the instance. Both are good faith dependent in the end, but one has a profit motive for keeping that faith.
Edit: I hope Stract gets there and takes off one day, but today doesn't seem to be that day for me.