It’s not uncommon to have a dominant internal jugular vein (IJV) i.e. one vein that is substantially larger than its counterpart on the opposite side.
Have you read @Jules post - ES Information: Background, Anatomy, Styloid Length, Angulation, Classic and Vascular - which covers the types of symptoms experienced w/ vascular & non-vascular ES? If you don’t have vascular symptoms then it’s likely what you’ve noticed is simply your dominant IJV.