If Apple releases a search engine that was even half decent, DDG would be in big trouble. Most of DDG users would jus move to Apple because they have a better 'privacy' brand.
How they better? I never heard who uses iCloud Mail for privacy rather than ProtonMail. It's just a company that makes the best major smartphone OS for privacy (there are only 2 major OS in western world).
You're saying Apple has better privacy brand than DDG? I'm not so sure about that, I don't think most Apple users connect the brand with privacy at all while DDG's brand (while much less familiar obviously) is all about privacy.