i used to use startpage before switching to searxng and its pretty good just the mobile app they beckon you to download is garbage and just chromium with a startpage paint job over it but if you just want the search engine for another browser its prob one the best
Not the OG, but I tried instances for awhile. After about two months I decided to self host it. The best instances for testing, imo, would be ones that have IPv6 on and nearest to your location for the host. They are aggregators so its tracking will be limited to the host of it. Even then, it’s a worthwhile test but self hosting can be as easy as installing docker, making a docker hub account, and pulling the prebuilt searxng image and going to the set port. That’s easiest way if you have reservation about data, but don’t have the time to configure the whole thing.
I'd say none will be private in the long term. Acquisitions ultimately break that eventually. It's hard to run a successful service and not get acquired, eventually. So, I have a self-hosted searxng instance. DDG has already started moving away from privacy and Startpage has some signs it might be moving that way in the near future. I'll let others comment on the current state of things at each, but if you give your search to any profit driven company it has the potential to be sold. But IMHO Qwant is currently the best option outside of metasearch engines with small nonprofit ownership, whoch can be unreliable, or self hosting.
Problem is that if a site gets too popular, then the search engines like google tend to start rate limiting. Before in started self hosting I jumped around every couple of months to a new server.
Of the three mentioned, maybe Qwant? I'm wary of any search engine that implements "AI", so DDG is out. Startpage — I can't provide a source, but I seem to recall there were misgivings to them in the past.