Uninstall preinstalled Edge

Windows still doesn't allow uninstalling the built-in Edge browser, not even in the Insider fast ring build 18970.
you can however use this powershell method to somehow uninstall it. i say somehow because the install files will still be in your system and another powershell command can reinstall it.

so open the PowerShell. Type PowerShell in the Search bar.Right-click and select Run as Administrator.
Type the following command and hit Enter
Get-AppxPackage

This will show you a list of all installed app. Look for Microsoft.MicrosoftEdge.
Copy (Ctrl + C ) or write down the PackageFullName.
Type following command with package name in it and press Enter.
Get-AppxPackage Microsoft.MicrosoftEdge_20.10240.16384.0_neutral__8wekyb3d8bbwe | Remove-AppxPackage

Done MS Edge will no longer work.