Google has mixed its search ads between and throughout the organic (free) search results starting sometime mid-last year. Google calls it dynamic ad placement, and it is an ongoing tests. In fact, Google had to change its definition of top ads to make way for this historically very unGoogle-like move.
The only reason Google is still my default search engine on desktop is …. dates.
I’m a dev and the date next to each search result helps me skip a ton of irrelevant links and get to the ones that most likely apply to my situation. DDG and other search engines usually don’t show any dates.
I’ve sent feedback to DDG on this but obviously that had no impact. If they add dates, I’m done with Google.
On mobile I still use DDG since my searches are generally not date specific.