I have a Samsung S5 mobile, running Android version 6.0.1 which is  Bluetooth paired with DJI Osmo Mobile 2.
I am not using the DJI Go App because it has too many issues to contend  with.

A very important function for my kind of video production is being able  to easily switch
between the mobile phone's front and rear cameras using the Power/Mode  button on Osmo Mobile 2.
(Three quick presses) Unfortunately this does not work.

Any feedback on this issue would be much appreciated.

Same on DJI mobile 3. switching cameras works well when the video is not recording, but as soon as I hit recording there's nothing I can do to switch cameras. Also the red recording button simply doesn't work I have to tap on the red button on the camera in the app still trying to figure this thing out.

I have the same issue with Samsung S10 Plus using Osmo Mobile 3. Any update, did you resolve this?