Am I missing something in the MIMO settings?  Is there a way to manually set the orientation of the app on the device? (in my case, a Pixel C tablet)

The app seems to be fixed on a single orientation.  The problem is that the orientation is upside down when using a Pixel C tablet.  With the placement of the USB-C port on the Pixel C, I can hold the tablet in landscape position, with the port on the upper right side, and the Osmo Pocket is correctly oriented (upright).  But the MIMO app is upside down on the tablet.  If I rotate the tablet 180 degrees (so the Osmo Pocket is now upside down on the lower left side of tablet) then the MIMO app is correctly shown, but of course the video from the camera is upside down.

I tried to "force" a fix by rotating the Pixel C and then locking the screen orientation.  I can open literally 10's of different apps and they all come up correctly "right side up" and function fine in that orientation. Even DJI GO 4 opens up in correct orientation.  But the MIMO app opens upside down.

I'm not aware of any fundamental reason that any Android app cannot follow the device's self-determined "which way is up" orientation.

Hi there, thank you for reaching out and we're sorry to hear about the trouble. With regards to your concern may I ask have you tried to use a different device just to isolate the issue? It seems the device you have is not fully optimized yet with the MIMO app. And make sure as well you have the required operating system for Android device as well. For your reference here's the list for recommended and tested device.

I am running Android 8.1.0 on the Pixel C.
The MIMO app runs in the correct orientation on my Nexus 5X using the same 8.1.0.
I don't think its unreasonable to expect a multi-$B company who sold me a $350 device to write Android apps that actively read the device orientation, rather than defaulting to a fixed/assumed position. Especially considering that one-person "companies" who offer free apps are able to do it.  
On the other hand, it seems VERY unreasonable to suggest I should go buy a Huawei tablet to "solve" the problem of DJI's own making.  This seems to be the default "solution" for every basic app inadequacy that users identify:  you tell them to buy a new phone or tablet.  How many users do you need to see react negatively to that behavior before you cease doing it???