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.