By default, each time you open Microsoft Edge, Microsoft Edge will check if its the default browser and will prompt a Would you like to set Microsoft Edge as your default browser notification with a Set as default button if not.
You can use the DefaultBrowserSettingEnabled policy to enable or disable whether Microsoft Edge always checks whether it’s the default browser when opened, and enables or disables the Make default button (user controls) in Microsoft Edge settings.
This tutorial will show you how to enable or disable the default browser check and setting in the Chromium based Microsoft Edge.