Last week Microsoft updated Edge. after which users started seeing pop-ups asking them to switch to Bing. If you don't want to see the prompts then you can follow this guide to disable them.
Edge 91 RSS
Microsoft is beginning the rollout of Edge version 91. It brings new shopping features such as Price History and Bing Rebates support, performance improvements, and new personalization options.
Microsoft is releasing Edge 91 later this week, and it will include improvements to sleeping tabs and startup boost that will make it the most performant browser on Windows 10, according to Microsoft.
Microsoft has released Edge 91 to the Beta channel with reading mode improvements, color themes, improved password management, and more. The update has begun rolling out to all Beta users.