Yandex is a much, much better search engine than DDG. The only irritating part about it that since it is Russian, it often shows many Russian sites in the top results. The best part about Yandex is that it also conveniently allows you to also search on Google or Bing if you don't find their result satisfactory. This allows them improve their search while also not upsetting their users.
If the goal of abandoning Google is about privacy, surely picking Yandex is counter-productive? Unless you make the conscious choice of having one entity keep the information from the rest, which I agree can make a lot of sense.
Realistically I don't expect any benevolence from any of the corporates that run all the popular search engines. (Even DDG is a private company with millions of dollars invested in it).
So my choice, as you rightly guessed, is limited to compartmentalising data collection, I also wanted to choose the best non-US competitor of Google - Yandex (Russian), Baidu (Chinese) and (later) Qwant (European). Yandex is the best among them.
To further compartmentalise data collection, I don't use Yandex exclusively and sometimes go directly to specialised sites for the answer. (For e.g. Stackoverflow for programming queries, IMDB for TV and movies, Wikipedia for some queries, etc. ... this is now easy since browsers allow us to add custom search engines to them.)
