I try not to buy from US companies these days, but Kagi is really so good that I make an exception here, despite the US government getting some of my money.
It's a matter of scale. Objectively, yandex is a great resource, and Kagi's results would be degraded without it. Pennies per user go to them. The sum of the entire money that has ever transferred from Kagi to yandex is what? 30 seconds of EU oil and gas purchases?
I use duckduckgo and live in a neighboring country, so I know Russian well (thanks, imperialism) and have to search things in it from time to time. It's still good at those queries, so this is just an excuse.