Thank you for your complete and helpful answer.
The door status must then: 1) be exposed via Matter by the Smart Lock; and 2) be supported by Matter controllers.
I have voted for DDP’s request so that at lest the first step is done by Nuki.
For the second step, I am not fully able to understand why other Matter door sensors (see e.g. Eve’s website) claim that the door status can be checked (“That all-important door, window, cabinet, or safety gate – don’t roam your home to confirm it’s shut. Just ask your voice assistant or consult the app of your preferred smart home platform.”). Maybe this aspect is not based on Matter?
In any case, I would expect it to be technically easy for Matter controllers to support the Door status, and a corresponding request can be made to the most popular companies.
Thanks again!