Panoramas seem to have reduced megapixel results

[FF22]

I recently acquired the Pixel 3. Took it hiking the other day and was capturing photos. When I got home I noticed that my Panorama shots were substantially smaller, about 2.5 megapixels, than the basically the same Pans I shot on my KeyOne which was about 7.5 megapixels.

https://forums.androidcentral.com/showthread.php?t=916709&p=6643005&viewfull=1#post6643005

I just checked and both are set to normally shoot 4:3 images and the Pixel 3 suggests that will be 12megapixels in its Settings. Yet the Pans are much smaller.

Any ideas?

Another Pan thing: On the KeyOne I can rotate the camera into Landscape mode and then I could pan up/down so, for instance I can get the full image of a taller tree or building. Seems that the Pixel does not support this type of pan. Googling, I think that older versions might have been able to do this or have I missed another setting somewhere.

Thanks in advance.