Hi Stella!
I’m so glad to hear about the positive changes you’re seeing since your ES surgery. I hope your recovery continues to complete eradication of your left over symptoms. Our bodies all heal at different rates, & it’s very hard not to feel a bit discouraged when reading a post by someone who basically felt back to normal a week after surgery (this is rare but does happen). I was in your camp & it took 9-12 months for some of my symptoms to finally disappear. After awhile I resigned myself to the fact I would just live w/ them but at the same time, I also learned I could mostly ignore them as they no longer had the impact on my life that they did before surgery. Happily almost everything finally resolved.
As far as your blood pressure goes, I do recall at least one or two other members mentioning a reduction in bp post op (couldn’t quickly find their posts). It was to a more normal level not below normal. I had the opposite problem where my blood pressure would drop too low during exercise, & I would feel like I was going to pass out. That stopped after I had surgery. Of course, I blamed it on my vagus nerve, which it most likely was but could also have been rooted in some additional nerve irritation since they all work somewhat together. The fact that you’re now able to be off bp meds is great news. I hope your bp stays steady as your healing continues. 
Here’s a link to the most recent info from @vdm regarding military neck: Question for those with military/straight neck (loss of cervical lordosis) - #23 by Isaiah_40_31