I have a Mavic 2 Pro Platinum and although the drone works, there is no picture on my phone when flying.  I am using the DJI GO 4 app on a iPhone 8 iOS 15.6.1.  I rarely use the drone and it has never been crashed or damaged.

Hi there. Thank you for reaching out and we're sorry for the trouble that this has caused. Can you please try to sync all of your flight records on the DJI Go 4 app and kindly please unistall and reinstall the DJI GO 4 app on your mobile device to see if the issue persists? Please keep us psoted. Thank you.

First port of call for me is to check whether the phone is connected to the controller, if so then check to see whether I have inadvertently set the camera's exposure settings to M, manual, with the manual settings resulting in gross under exposure. If so switch the camera back to auto exposure  of chnge the settings to give the correct exposure.
So far those have cured any black screen for me.