You're right but at the same time they say that they source their "traditional links in the search results" from "multiple partners", which to me seems to imply that it's from partners only and not their own crawler.

Try searching for something random like "woxioai" on DDG and you will see that the search results are identical to Bing (albeit a slightly different order but I presume they do some internal sorting at least), while the search results are completely different on Google.