How about Bing? Yes I know, they're easy to forget about, but....
Bing started 15+ years ago as a feature for feature clone of Google. Historically they've simply crawled Google results and replicated whatever Google returns. It could be a data point that Google has made the perfect search system as of 15 years ago - or just a footnote of the balmer era of Microsoft like Windows phone.
DDG doesn't really qualify here as they aggregate google/bing search results.