@IJVman - Very nice images! I tried downloading the dicom library link, & it just gave me a blank page. Did you intend for your full set of images to show up via the link?
It looks to me like your IJVs are pretty even in size i.e. you don’t have one that’s particularly dominant. That is a good thing. I also agree that your styloids are tremendously long & thick at the skull base as @MGORNEAU noted. The joints indicate it’s more styloids adjoined by calcified stylohyoid ligaments than just styloid elongation, & as @Jules said, they’re nearly calcified to your hyoid bone.
I also agree w/ MGORNEAU that the space between C1 & the styloid looks tighter on the right than the left. That may mean a left styloidectomy could allow the left IJV to decompress, but you’d need something to be done to C1 on the right in order for the right IJV to decompress adequately. That’s probably not something you wanted to hear.
The greater horns of your hyoid bone also look quite long to me & appear to be very close to your cervical spine. Do you hear or feel clicking when you swallow or have pain or difficulty when swallowing?
Your cervical spine is extremely straight (military neck) which also effectively brings your styloids & hyoid closer to vascular & nerve tissues. The normal cervical curve can be restored but that takes time & patience, & in your case, I think any effort to try to fix that should come once your immensely long styloids are significantly shorter. You can get some insight about how to do that via this post: