Unable to install Network Extension of System Extension, stuck on validating

I'm trying to create a network extension packaged as a system extension on macOS,

let request = OSSystemExtensionRequest.activationRequest(forExtensionWithIdentifier: "com.example.Desktop.PacketTunnelDesktop",
                                 queue: DispatchQueue.main)
            request.delegate = delegate
            


            // Submit the request to the system.
            let extensionManager = OSSystemExtensionManager.shared
            extensionManager.submitRequest(request)

The application is installed in /Applications, I have also turned off SIP and systemextensionsctl developer on

I'm not getting any breakpoint hits on my request delegate, but I am getting some logs in the console app:

making activation decision for extension with teamID teamID("XXXXXX"), identifier com.example.Desktop.PacketTunnelDesktop

no related kext found for sysex `com.example.Desktop.PacketTunnelDesktop`

extension XXXXXXX com.example.Desktop.PacketTunnelDesktop (1.0/1) advancing state from validating to validating_by_category

validate: category: com.apple.system_extension.network_extension, extension: com.example.Desktop.PacketTunnelDesktop

waiting for external validation of extension with identifier com.example.Desktop.PacketTunnelDesktop

It seems to stop here, and running systemsextensionsctl list shows:

[validating by category] as the status.

I'm trying to find some barebones example code for a network extension packaged as system extension but couldn't find any. Any ideas where to go from here?