If you are having issues with downloading Microsoft Edge, then there can be two reasons behind it. If it’s not working because it is not supported on your version of Windows 10, then we suggest you upgrade to the least supported version of Windows 10 it is supported using Rufus. So make sure you have the right version of Windows 10 or macOS. It’s also available on macOS 10.12 Sierra or higher. If you are using Windows 10, Windows 8 and 8.1, and Windows 7. Microsoft Edge is currently available for both Windows and macOS.
If you cannot download or install Edge using the installer, use Windows Updates and see if it helps. You can download it from Chrome Store or use Edge Legacy to keep using the older version.
Note: If you are not able to find your extension after Migration, then its probably because the extension is not available for the new Edge, which is based on Chromium.