If your symptoms started after your sinus surgery, it makes me wonder if you have a chronic CFK leak (spinal fluid leak). I have hEDS (Ehler's Danlos Syndrome), POTS, dysautonomia, MCAD, a chronic CSF leak in my lumbar spine, etc. I am prone to CSF leaks and have been dealing with one in the last year.
A chronic CSF leak can cause POTS and autonomic dysfunction. Look up Dr. Ian Carroll on YouTube. He explains how a chronic CSF leak causes POTS and how some people have recovered after fixing their leak. If you have a cranial CSF leak. Getting some who understands chronic leaks and knows how to fix them is extremely difficult. My leak symptoms were overlooked by multiple neurologists and neurosurgeons. Finally I told a neurosurgeon that I thought I had a chronic CSF leak and they "ruled it out" with MRI with contrasts, which rarely finds CSF leaks. Then I saw a neurologist who said he ruled out a CSF leak with an MRI with and without contrast to check CSF pressure, which rarely catches a chronic leak. Finally a new primary care doctor familiar with Chronic CSF leaks said I needed a CT Myelogram and she got my pain management doctors to order the testing. Sure enough I have a leak in a nerve root in my lumbar spine. I had a blood patch that worked at first but starting leaking again. Having a connective tissue disease (EDS) makes it hard for me to heal. Trying to get someone else to fix it currently.
Duke University and Cedar Sinai in Southern California both deal with cranial leaks. (They have YouTube videos as well that are helpful). Dr. Ian Carroll at Stanford doesn't deal with cranial leaks that I am aware of.
Do you have have sinus congestion, a runny nose, or post nasal drip? If so, it could be CSF fluid. CSF fluid tends to taste salty and even sweet. Do you get headaches?
With the GI issues and having been on antibiotics, have you been tested for SIBO (small intestinal bacterial overgrowth)? It can happen in dysautonomia but antibiotics can cause it as well. SIBO alone can cause a lot of problems, even systemic issues especially since it can lead to leaky gut. It can also cause GERD. If you are on H2 blockers or PPI's for the GERD, either can cause SIBO, make SIBO far worse, and make all sorts of health issues worse. They both interfere with digestions and absorption of nutrients. GI issues usually get worse in general on H2 blockers and PPI's. And PPI's can increase your chances by up to 50% for chronic kidney failure. My GI doctor referred me to siboinfo.com and a naturopathic doctor for more information about SIBO. Naturopathic doctors and Functional Medicine doctors have been dealing with SIBO much longer. My GI diagnosed it and treated it multiple times but doesn't understand diet, nutrition, and how to address motility issues to address SIBO after it is treated, which often means it will just come back.
Also, research zinc carnosine for reflux. There are medical studies out there about zinc carnosine. It helps me with GERD and gastritis better than H2 blockers or PPI's. It's awesome stuff. It was prescribed to me by my Functional Medicine Naturopathic doctor and it has been a game changer for me.
Getting checked for delayed food reactions can be helpful too. My PCP had me do USbiotek testing for food triggers.
Do you take magnesium? Vitamin D? Both are really common deficiencies. I am prone to vitamin D deficiency and my PCP said up to 80% of people in first world countries are deficient and magnesium is super important for many things.
MTHFR and partial methylation defects can cause a lot of problems too.
Also, there is a private CSF leak on facebook that is full of information and resources.