Do you want to keep Bing as your default search engine but sometimes you need other's? This open source extension adds buttons to quickly search using other search engines such as Google, Brave, Mojeek and SearXNG.
If you're using Google Chrome then follow this tutorial: https://youtu.be/rO6Nhwu8uMo
DuckDuckGo and Ecosia uses Bing's index. meanwhile, Startpage uses Google's index.
Mojeek and Brave offers independent indexes.
SearXNG is a popular metasearch engine.