Obviously you didn’t actually look at the paper this article is about. While Google has been getting worse over time, DDG is even worse. It is the worst browser by the metric they are measuring (DDG is 31% spam vs. Bing at 23% and Google at 9%)

I would recommend trying a SearXNG instance if you haven’t before. You can combine results from multiple sources. I use Google as my main source while also having access to the DDG-style !bangs.