DuckDuckGo is partly based on Bing (a blend of Bing and Yandex, when its sources were last heard of). It appears to be unknown if there has been a back-end ingestion that makes it a replacement for Yippy. But a few initial tests suggest it might be a reasonable replacement, and may have had some of Yippy’s weightings plugged in. For instance try a search for…
“href.replace” regex script
But if you want a technical search for your field or hobby in 2021, with full indexing reach and relevance-ranking, it’s probably best to create a Google Custom Search Engine (CSE) and populate it with about 100 or so of the top relevant URLs.