Microsoft Edge was installed in Windows 10 via the update via the KB4559309 update installed via Windows Update. Windows 10 does not allow you to uninstall the new Microsoft Edge via the uninstall programs section of Apps & Features. That does not mean you cannot remove it via the command prompt. Uninstalling Edge via command line means you can now have access to Edge Classic. If you do not wish the Edge update to install automatically again, you can manually download and install Microsoft Edge or block it from being installed.
Source: https://www.bleepingcomputer.com/news/microsoft/how-to-uninstall-microsoft-edge-forced-installed-via-windows-update/