There’s folder on the Android device you need to save somewhere safe until everything’s sorted.
It’s the folder …
DJI/DJI.GO.V4/FLIGHTRECORD
… AND the subfolders and all files!
Once you have everything working, you should be able to copy that data back and sync it OK with Go4.
At least the .txt files in that folder can be uploaded to AirData to see the flights.
(AirData is better than the log in the Go4 app, anyway. 
)