OK but how is it free?
The same way duckduckgo is free
Ads? I genuinely don't know. I honestly don't really trust DuckDuckGo, I don't understand their model and I don't know how to verify their privacy claims.
https://duckduckgo.com/duckduckgo-help-pages/company/how-duckduckgo-makes-money/
Ddg monetizes via microsoft ads