The left side of the panorama is much brighter than the right side regardless of what the camera did.
As you’re panning and taking the picture,the camera is on autoexposure. What you’re seeing is an exposure change occurring during the panning of the panorama.
Camera starts out seeing dark then as you spin it’s sees bright and adjusts the exposure accordingly.
In this case the end result sucks because everything is on autoexposure.
To prevent this, set the camera to autofocus lock and auto exposure lock by pressing and holding on the screen on the most important part of the panorama before shooting.
If you lock first, the end result will have perfect exposure where you chose and everything else will fall either brighter or darker