My Mayo doctor said 1 in 6 Nissen operations go bad and/ or have negitive complications.

I would suggest to have an esophagram and barium swallow done to check the severity of reflux and to also have an esophageal motility study done to see if you swallow is normal. If it is have the LINX band placed.
I just went through all this last Dec. and had surgery in Jan 2019. I had a rerepair of a large hiatal hernia, the slipped wrap from a a 24 yr old Nissan was removed,so my stomach is normal now and LINX band placed. I'm reflux free for the first time in 30yrs.
If you get the LINX band you must eat every 2-3 hrs for at least 3 months to stretch the band while scar tissue forms around it so as to prevent the scar tissue from creating a stricture enveloping the band and making swallowing more difficult.
Once the reflux stops you can wean off the PPIs. I've weaned very slowly off my prevacid because I was double dosed for many many years. I've read that you can develop really bad rebound acid production if you don't. This week is my last week of prevacid where I am only taking 2 for the whole week. Yeah!
This month I am having my 1st Endo since surgery to see if the last 2cm of Barrett's just above the LES healed up. If not this will be RFA #6. Hopefully it will be the last. I use to have 8cm of Barrett's and medicated for over 24yrs with PPIs. This alone will depleat your B12 stores and cause Calcium loss in your bones.
Make sure you know what your bone density is and your B12 levels because your binding capacity will be low.
Good luck with everything 🙂