I'm pretty sure DDG used to use Yandex... which in turn used Bing. Now DDG uses Bing directly.

The world of search engines is nearly as frustrating as the world of web browsers, or dare I say Linux distros; on the srface, a lot of choice. But, underneath, much of it is just the same old thing, with a different front end.

yes, for the most part, there are evidently some custom algos in there but most results are from bing.