Only downside is losing recorded audio captured in 720p cache videos.

Haven't tried yet with 4K, that would be interesting to see working, too. Unlike movies I created from the 720p cache videos, I've had no audio dropouts, audio/video stays in synch for precise scene transitions, and final output looks to be 1080p. The first free form movie I created using 1080p source files turned out nicely. I actually find it easier to use a PC to select which MP4 files to copy. I use an OTG cable with SD card reader to copy the source files from the Mavic SD into the DCIM folder on my Android phone, but there are probably other methods. Happily, it doesn't recopy the video files, it just creates metadata (not sure where) linking to the those MP4 files, so they appear in the DJIGo4 Album, and are available in Create Movie Free Form or Create Movie AutoEdit. DJIGo4 Editor's import feature (upper left arrow icon in the Album) will see those MP4 files and let them be selected for import into the DJIGo4 Album. The key step is copying 1080p source files (MP4, in my case) from the Mavic SD card to my local Android device DCIM folder. It *is* possible to quickly import 1080p source files from the Mavic SD into DJIGo4 via USB, vs.

How to use dji editor