Microsoft Edge 91 was released last week and users began reporting startup bugs and nag screens. Microsoft pushed out what appears to be a configuration change, and users are now saying the bugs are fixed after restarting the browser. It is not clear what Microsoft changed to fix these issues, but you can now close the browser and restart it again for the fix to go into effect. The fix was tested by Opera, and we were able to test the new configuration changes and the issues have been fixed on our end.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-microsoft-edge-91-nag-screens-and-startup-page-bug/