OK I see, will investigate this further. Now that I think of it, perhaps O&O ShutUp10 also plays a role in this. But I can still configure Cortana in the Settings app, so I don't think it's fully disabled.
There is also UninstallView which, like O&O, you do not even need to install on your system: https://www.nirsoft.net/utils/uninstall_view.html Acadia
Good idea, but I now see that Cortana isn't listed there either. So I wonder if it's because O&O ShutUp10 has disabled Cortana. But in C:\Windows\SystemApps\ I can still see many entries related to Cortana. However, in the Settings app I can only choose which language Cortana should be using, and there are no other options, so I guess it's cool.
BTW, this may indeed be the case. Because seems like O&O ShutUp 10 can't disable Cortana, I will probably need to apply some registry hack, because the trick with PowerShell also didn't work, see second link. It's like freaking spyware, everytime you kill the Cortana process it reloads automatically. The strange thing is that the Cortona process is never visible with tools like Process Explorer but it does show up in Win Task Manager, I wonder what that's all about. https://www.howtogeek.com/265027/how-to-disable-cortana-in-windows-10/ https://www.tomsguide.com/news/how-to-uninstall-cortana