Edspilot
Yep your bang on with what your saying, the wobble and pulsing of motors occurs when flying straight at speeds over 10 mph, this is also true when going sideways and in reverse.
I even disabled all the sensors in the app but still the same.
My theory especially with the camera horizon being back to front is that the IMU calibration is also calibrated on the wrong sides of the aircraft, unfortunately you can't overcome this by doing the opposite when calibrating as the software simply puts the side it wants in the position it would be if calibrated as per its requests.
I'm sure DJI will come through with the fix soon, but if you haven't already I urge you and everyone to make known to them at your earliest opportunity.
Edspilot
You don't need to fly the drone to test the horizon defect, just fire up everything without props on (for safety indoors) and enter camera view, then select adjust gimbal roll in gimbal settings and click away with the drone on a flat surface.
It will soon become apparent that it's back to front
Let me know your findings
IKW