More information that I mentioned I would provide.
I have attached a video that shows the process that I went through to not have to Turn on PTP mode everytime DJI GO4 was launched and connected with my Mavic Pro.
Power On Mavic Pro
Connect USB Cable to side port on RC and bottom USB port of Moto X or G4 (untested with G4)
Clamp phone in between RC side holders
Turn on Screen Rotation in swipe down settings so DJI GO 4 App will rotate to Landscape mode instead of staying in Portrait Mode
Turn on Remote Controller and allow to connect to Mavic Pro and populate the display on the Remote Controller.
Launch DJI GO 4 app
Swipe down from top of screen and double touch / tap USB Debugging. Turn off USB Debugging within the settings
Find notification about USB Charging by swiping down again from top. Double Touch / Tap USB Charging
Touch the option presented for PTP rather than the top option that lists USB charging only.
Then a pop up message "should" be presented asking if the default should be PTP for DJI GO 4.
Tap the small check box and then tap Enter. There will be a message presented about inconsistient Firmware.
I ignored it by clicking Cancel
Then the DJI GO 4 app will display all details and allow operation of the Mavic Pro.
There is a very good chance that the Moto G4 will behave identically to the Moto X albeit with a slower processor as these are similar devices.
Watch Video here