@eskimo is it possible to make that post with the developer ID details the accepted answer? I actually gave up on developerID for a day or two until I eventually came back here and scrolled to the bottom.

Ask on the Cisco forums.

You should contact that developer, but they are probably testing it.

Do you mean "now" creating a Network System Extension? I did actually look at the console log. As it happens I opened a TSI because money is no object and I have a few lying around for free anyway. If we solve it for general we could post it here. Thanks for the information on the os_log. Is that also visible in the Console.app in the Devices streaming part?

you should test yourself via TestFlight, running using Xcode isn't a valid way to test.