From engineering standpoint there must be like 7 degrees offset in a driveline that includes universal joints.
I'll be honest too. I know a litlke more today than i ever understood completely.
Your engine isn't in the center of the engine bay.
The trans tunnel isn't in the center of the floor pan. Driveshaft meets differential at an angle.
How did they make this 4 wheeler track anywhere near straight?
Go measuring around and you'll find some clues.