[Solved] How to remove the SoftRAID kext from the extension folder?

After uninstalling SoftRAID 6.1 from the menu option in the SoftRAID app, and rebooting.  I notice that the kext and the application folder is still around.  I was able to delete the SoftRaid folder from the /Applications folder

% ls -l /Library/StagedExtensions/Library/Extensions/
total 0
drwxr-xr-x@ 3 root  wheel  96 Oct 20 20:48 SoftRAID.kext

The extension doesn't appear to be loaded

% kextstat -l  | grep -i "softraid"
Executing: /usr/bin/kmutil showloaded --list-only
No variant specified, falling back to release

Removing it doesn't seem to be allowed:

% sudo kextunload /Library/StagedExtensions/Library/Extensions/SoftRAID.kext
Executing: /usr/bin/kmutil unload -p /Library/StagedExtensions/Library/Extensions/SoftRAID.kext
Error Domain=KMErrorDomain Code=3 "Error occurred unloading extensions: Missing extension with identifier com.softraid.driver.SoftRAID : Could not find: Extension with identifier 'com.softraid.driver.SoftRAID' not found" UserInfo={NSLocalizedDescription=Error occurred unloading extensions: Missing extension with identifier com.softraid.driver.SoftRAID : Could not find: Extension with identifier 'com.softraid.driver.SoftRAID' not found}

% sudo rm -rf /Library/StagedExtensions/Library/Extensions/SoftRAID.kext
rm: /Library/StagedExtensions/Library/Extensions/SoftRAID.kext/Contents/_CodeSignature/CodeResources: Operation not permitted
rm: /Library/StagedExtensions/Library/Extensions/SoftRAID.kext/Contents/_CodeSignature: Operation not permitted
rm: /Library/StagedExtensions/Library/Extensions/SoftRAID.kext/Contents/MacOS/softraidd: Operation not permitted
...
...

Manual removal seems quite involved: https://grafxflow.co.uk/blog/mac-os-x/delete-ioplatformpluginfamilykext-macos-big-sur