If you are buying silica gel desiccant try to get the sort that is self indicating. This normally changes color dependant on moisture content. Then you just pop it into and warm electric oven at 110°C or microwave to drive off the captured...
The bit that’s bonkers is the lengths that DJI have gone to lightening everything else and then they throw away the weight margin they’ve gained by using 1.8g for a speaker. They even screw the thing in place using 2 screws when a clip and 1...
You said you calibrated the compass and IMU. They really don’t need calibrating unless they are showing errors and there is always the chance that your recalibration is worse than the factory calibration.
When I did my systems checks DJI Fly gave...