Consider other raw converters, C1 (Capture One) will also crop by default. PLEASE NOTE, the exif of the camera is telling LR what to do as it's a mirrorless camera. LR is doing with DJI is telling it to do. Not vise versa.
Capture One will allow you to expand to the full size, and if you want a free one, consider Raw Therapee note the spelling. Both will allow you to over ride the built in crop.
Paul C
I am installing therpaee now and give it a try, though I feel a bit of reluctance to switch from LR. Is it possible to save the "uncropped" raw in therapee and then open it correctly in LR?