I mean, exactly how invasive are default operating systems? (Like Windows, Mac, Chrome OS, Android, iOS) Do they log your keystrokes, log passwords, capture screen, upload your photos, videos, or audio? (Assuming you aren't a target of government) Is it even possible for the average person who doesn't feel comfortable messing with installing operating systems to have any privacy?
I would say there's an argument to be made against duckduckgo with how they're not open source, and the whole allowing Microsoft trackers deal, but it is definitely a better option than google or bing. I don't understand why you're mentioning their browser however, as there are definitely much better alternatives.