Insurance denying surgery as "experimental" when there’s plenty of history on this disease stating the contrary

My insurance denied to cover me for a surgery while my quality of life is destroyed from my illness. It’s progressed and caused more issues and may eventually kill me. Any tips or advice on what to do are greatly appreciated.

Quick summary: Years of GI issues that started with burning above bellybutton and some occasional diarrhea but the burning was the most prominent and most frequent. This progressed over time while getting ignored by doctors to chronic gastritis, pain, vomiting (yellow and after id wake up), probable sliding hiatal hernia (seen on upper scope in January but then not on a scope by another doc in may) gerd, lpr, shortness of breath, rapid weight loss with fluctuating weight depending on symptoms, constipation and diarrhea. I’m probably missing some stuff but this is the highlights. Bile was found in my stomach on a scope and it looked like my vomit when at my sickest. This is what is believed to be the root of all of my medical issues with how the origin of this started and how its progressed.

The burning and chronic gastritis were the early things while the last year and a half or so (maybe two) the vomiting hit hard, the hernia symptoms, gerd, lpr all hit me, lost 20% of my weight in 3 months, etc…

Where I’m at currently: So fast forward to today and I got a consultation and approved for surgery with a surgeon who has did the surgery for bile reflux multiple times with patients like me. Well, he submitted the claim with insurance and they denied it and just said cause it’s “experimental” but didnt give me details as to why they believe that. This turned into a peer review with an external insurance company and they also denied it and said it was “experimental” and that my BMI didn’t meet the requirements and the surgery was for weight loss. The Dr. explained during the consultation that it wasn’t for weight loss and explained how the surgery wasn’t the same and how it doesn’t go nearly as low as the weight loss surgery, how it was made for bile reflux, how theres history and cases over it, how I match the conditions with all the years of testing, treatments tried, progression of illness, findings, etc… They still denied it and the only reason I get is cause of my low BMI (bile reflux gastritis causes this) which tells me they did zero research into this because they didn’t even address what my doctor mentioned and stuck with the easy answer of it being for weight loss and I wasn’t qualified for that. Specifically, the surgery is the Deemester duodenal switch which was made in the 80s by a doctor to treat people with bile reflux gastritis. It reroutes your intestines so bile enters your intestines roughly 4 feet lower into your intestines to keep it from refluxing into your stomach, but not so far down to keep malnutrition from occurring. For reference the weight loss version goes about 11-14 feet down your intestines from what I recall and it takes out part of your stomach. Not the same and yet they deny it and act like I’m trying to get the weight loss duodenal switch

What are my options now? I got some ideas but I want to see if anyone else has insight into this. I need this surgery and it’s happening one way or another because it’s getting worse and now causing issues beyond my stomach. I had a nurse tell me if I keep getting damaged I could become septic and die. This doesn’t even include the other dangerous effects i could get from all the issues now happening in my body. I haven’t been able to get it under completely under control with diet change, lifestyle change, fasting before bed, elevated sleeping, meds, etc… I only got it enough for me to not be vomiting as soon as I wake up and it’s intermittent instead of constant, but I still have daily issues all while I struggle to work full time to have insurance that they are keeping me from using. Now what?

Tldr; got approved for a surgery by a physician and insurance denied it, then it went into an external peer review and got denied being stated as “experimental” and the specifics they gave showed they don’t even understand the condition or surgery I need which is well documented, including sources like the mayo clinic. I even had a nurse say with how things are progressing I could eventually die from this. Advice?