Exactly. Replacing the sky is easy … if you want to do that in PS.
But [stuck record alert] … this workflow is not about “replacing half your image” with someone else’s photo. That said, there are times when you want or need to, in that case … go for gold.
eg: this hi-res pano that needed a lot of work in Hugin to get the correct sand ripples to stitch to the correct sand ripples - but having done that my leg shadows had moved and are “fractured” - LOL!
I have seen videos on YT where the 26 images are taken then the drone is handheld and 5-7 images of the sky are taken, these are added to the 26 pano images and stitched, no filling in or sky replacement needed. I have a DSLR with an 7.5mm fisheye lens, when the wind stops blowing a gale and the rain decides to give us a break here I am going to experiment, I figure with the fisheye lens I will only need one sky image and any edge distortion will be hidden in the overlap as I only need to use the centre part of the image. If I leave the drone up there I could even get the drone in the finished pano.
Another consideridation with processing the topmost sky section is that, in many cases, there are clouds, and typically, these clouds move between each of the 26 captured images (unlike the ground, which is relatively static). Which is why DJI and my workflow above uses a method to blend/smooth this movement.
But there is sea, lakes, rivers … and, of course, whilst not moving, there’s the stitching impossibility of sand ripples in my example above, and fields of corn can be equally/more challenging.
But agree on trying to match a DSLR clouded sky … matching focal length, barrel distortion, colour temp … and moving clouds … I don’t see that it’s worth all the effort to fake something.
If you REALLY want a non-faked full 360, then a Parrot Anafi is the drone to get, with its gimbal that does point straight up.
My workflow is very similar, but I use Microsoft ICE and Affinity photo. I don’t bother too much with sorting out the sky because I imagine the bird’s eye view is a chance for people to see what’s below, not above. If I can I’ll hide under a tree or behind a wall so I’m not in the photo but where that’s not possible you can usually spot me in that bright green hiking jacket, kind of like a signature.
From a few updates ago to Windows 10 ICE is prevented from running. B******s.
I now use AGP (with a c***k - well, no one is losing any money as it was ‘terminated’ a while ago) but ICE was so much easier and usually did an excellent job.