I have no idea about kuula.
Does your original Panno009 image have the correct width to depth ration of 2:1?
It looks like it does not.
Where as; Salvonc(10) probably does have a ratio of 2:1.
A full 360 pano from an
M2P will produce 25 or more images.
When stitched the result will probably not be the correct ratio so you have to edit the file in something like GIMP.
Many stitching programs will not accept the DNG format. I think that, it is something to do with the fact that the files are not pictures as we understand a picture to be.
You either shoot in jpg in the first place or convert DNG to another format (RawTherapee) before trying to stitch them.
I use MS ICE and stick with jpg files as the originals. After stitching I use GIMP to resize and scale to a the correct ratio width to height. (twice as wide as it is tall) Then use Rioch Theta or Insta 360 to view.
You can fill in the sky with a false ceiling if you want, and/or use skyfill to do the job
but unless you have a clear blue sky there is always a trace of something not quite right.
Skyfill does allow you to create a mirror globe in the sky above the photo position if you wish.