Rather than a focus issue, could it be that you've got subjects with light areas that are overexposed and brighter than the other parts of the scene?
I did a quick tweak of shadows and highlights.
Is that any better?
If you'd shot on an overcast...
More info ?
How long is it taking?
Has this just happened once or multiple times on the same day?
How long was it since you flew previously?
Confirm that the drone has a clear, unobstructed view of most of the sky?
I proudly served in the Navy and had my last year during the Gulf War, received a medal of commendation for finding a crack in a tail rotor blade that was missed earlier that day while parked in the stack. The pilots and aircrew were sitting in...
Whatever settings are right for the subject, the lighting conditions and the desired look of the images.
That's why cameras have so many settings and adjustment possibilities.
There are no magic one-size-fits-all settings.