DJI Osmo 4 produces a .LRF file along with the main video. This is a low resource file, lower quality and resolution, ideal for use as a proxy. The only change is the extension. To use as a proxy, currently I have to rename to *.LRF.mp4 a silly step plus a possible chance of overwriting the fullres footage.
If the LRF file was recognised then using proxy footage would be so much easier. They are effectively mp4 containers with just a different extension.