Personally I've had symptom relief immediately after surgery in each of the 5 surgeries I've had over the past 10 years.

I have a VP shunt for congenital hydrocephalus and have experienced similar symptoms when my shunts have failed, including the dizziness, but again almost perfect after surgery. I even had my shunt disconnect six years ago, and again perfect after surgery.

The only lasting "symptom" I've ever experienced long term was a pulling in the shunt tract after one surgery, but I genuinely believe that was a botched operation; that "pulling" eventually led to the disconnected shunt I mentioned and required a second neuro to figure it out and fix it.

I do feel for you on the diagnosis, until I learned to diagnose my symptoms on my own the typical time between failure and surgery was about six months for me. That was hell of course, with the dizziness, headaches, nerve issues, etc. But after surgery all has been fine each time.