unlike other sites like DDG actually has its own crawler whereas most alternatives are just frontends for google/bing

Just so you know, DDG does have its own webcrawler (DuckDuckBot). It takes results from that, and the Bing API, and other sources, to generate results.

Also, they pay Bing for results from the Bing API (which as I understand it gives configurable access to the Bing index) and so even the results that do come out of Bing are quite different than you’d get compared to just a “frontend for Bing”.