A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
A better answer would have been - this functionality isn't available (as per my research and in your reply) but a good work-around is to initiate a meeting from the Teams Rooms device, and then invite yourself to that call. This then places a copy of the Whiteboard into your own account (access via app or whiteboard.microsoft.com) which you can view and export as usual.