Yes ... it would be impossible.
Because the camera on the drone has so much depth of field, the only way you could have the subject in focus and everything around being soft would be to focus on the subject at 2 metres.
At f2.8 that would give...
If it was a focus issue, the things behind the trees wouldn't look sharp.
If you are getting more shots like this, I'd suggest using the 25 MP mode and see how that handles things.
The 100 MP mode doesn't really add anything positive but maybe...
Are you sure it doesn't autofocus?
Is it giving results that aren't in focus?
With the huge depth of field, it would be an uncommon panorama composition that needed precise focus anyway.
Do some comparison testing.
I quickly abandoned the 100MP...
Are you getting images that aren't properly focussed?
Fun fact ... you can shoot panoramas all by yourself without using some lame automated feature.
It gives you a lot more creative control.