You may have already seen this in the Resources section, but here's a link to my early recovery journal.
If you scroll toward the end, I make some comments about surgery failures and successes. You might find them helpful.
The surgery isn't something to be taken lightly, but should be a last resort. It sounds as if you're getting to that point.
Keep in mind that you get a skewed view of Nissen success rates when you frequent online forums. Most people have the surgery, and go happily on with their lives and never post on a forum at all. Generally people who seek out internet forums are having problems and and looking for answers. There is a high percentage of positive outcomes, so don't let internet horror stories scare you.
I was also scared, and held off far too long. As a result, I have permanent health problems due to overuse of steroids that were taken to counteract the inflammatory effects of GERD on my lungs. I wish I'd had the courage to act sooner, before these things happened to me. Like you, I was fearful as a result of reading frightening stories online.
Good luck with you decision! This forum is a great place to get information and receive support!
Words of wisdom by Eckhart Tolle:
"Whatever you fight, you strengthen, and what you resist, persists.”
“Worry pretends to be necessary but serves no useful purpose”
“Accept - then act. Whatever the present moment contains, accept it as if you had chosen it. Always work with it, not against it.”