It is a "feature" added to "improve experiences across Microsoft products". With one of the recent updates it gets enabled for all Edge user profiles, and you get a flyout notification, that navigates you to the setting where you can disable it.https://support.microsoft.com/en-us/topic/learn-more-about-search-and-service-improvements-in-microsoft-edge-5b95a197-6311-4976-ad33-4aad57a9ce65