As of 8th December 2021 update the Teams Display supports portrait mode for Meetings and calls, as shown in the extract from Message Center post below.
You will note that this is only for Calling and Meeting screens. I’ve been eagerly awaiting this release, so I thought I needed to try this out, as the camera position in the Teams Display is a weak point for me. Even though it is situated on a shelf on my desk, the camera is till a little low.
As my display does not support screen shots, I’ve used photos of the device. I’m not a photographer.
Conclusion: Nearly solves the limitations of the smaller Teams Display device, but really needs to be for all areas, not just meeting & calling.
After doing the update you will notice that most screens do not work in portrait mode, this includes the calendar, home screen, chat, teams.
However as soon as you join or start a meeting/call with the device in portrait orientation, the device detects the orientation and rotates the screen automatically. Portrait mode is not really supported on the join screen, but it is still useable in either orientation.
Once in the meeting both Landscape & Portrait mode work well.
The Teams Queen Blog 