I couldn't help myself. I had to do one last phone experiment. I finally remembered that my Lumix LX100 takes panos in much the same way that my A51 does. I can't think why I'd hardly used the facility. Anyway I thought it might be fun to compare results from the two of them.
My best revised guestimate of the effective focal length of the phone in wide angle mode is 14mm ffeq. I know that the Lumix manages 24mm ffeq. Anyway, here are the two samples, shot in the Megalong Valley this afternoon, both cropped to an aspect ratio of 2.65:1 which, incidentally, is the old, original CINERAMA ratio. Why not?