A while back I wanted to transfer a waypoint mission from the iPad to my Phone and there is a thread where I talk about how to do that and where the files are located...
In case it helps anyone, I took a log file from a previous run of my way point mission and converted it to a GPX file and took that into Google Earth Pro. Then I went to the Fly app and loaded up my re-created version of the deleted way point...
Tell me about it - I got to my construction site this AM and had to rebuild my progress mission from scratch. I was not pleased. According to my research there is no way to back up the waypoint missions at this time.
Just as a heads up - After I updated to the new version of DJI Fly (1.17) yesterday it deleted my saved waypoint flights. I am sure it's related to the cloud save for the waypoint flights that is not available in the US yet (if ever).