8sec is a HUGE slow exposure. Almost no way you won’t get some movement.
It’s true that you CAN do up to eight second exposures, but I cannot imagine anyone getting an actual sharp image unless it was sitting on the ground at that shutter speed...
I agree with Meta4's comment that it would be worth learning why this is happening rather than working around it by shooting in panorama.
From what I can see in your examples, the panorama is just more processed than the other photos which...
For anyone wanting to achieve the best possible IQ there is only one way and that is shooting DNG and "develop". There is obviously more work involved because all raw files need to be "developed" using specialised software such as Photoshop or...
For myself: I look at JPG as a compressed, lossy format specifically tailored for immediate viewing and ease of sharing, I always think in terms of a JPG being like a Polaroid Instamatic... okay for a cursory look, but no good if the image is...