In this chapter of our Microsoft Flight Simulator 2020 game guide, we explain how to disable the HUD screen interface displayed in the external camera view.
If you want to take interesting screenshots of the plane from an external camera (End key), the screen clocks and indicators may obstruct your vision. For now, there is no option to turn them off with a key. You have to do it in the options menu:
Go to - Options->Camera->Chase Camera->Instrument Heads-Up Display->Off.