Hi,
ok, so you have confused many concepts here.
first, in non mobile mode, you use the mouse to rotate the camera, in mobile you don't have that, so your camera is never correcting the direction.
also, in your InputDirectionCompass, why are you not also making the CameraAutoLookAt the target of your look at for mobile? it tries to rotate another object, that doesn't make sense.
on mobile, you'll need to have a dummy object attached to the Model placeHolder, which represent the camera position. then have your camera position to move towards that dummy, and you are done with it.
If I attach the camera to the model placeholder, all is good, but to abrupt, do as I mentionned above to put some smoothing.
another way would be to use SmoothLookAtDirection for the camera on mobile. Get the direction of your player using TransformDirection, that works as well. you might need some fiddling on that to get it right.
I got it to work: check it here:
https://imgur.com/3Rlci7qBye,
Jean