Diabetes Insipidus with lack of ADH & Sphincter of Oddi spasms

For the Db Insipidus, the Desmopressin should definitely work. It will just take a little time to get the dose adjusted just right. It causes you to retain water and relieves the dehydration. It replaces the ADH you are deficient in.
For the GI problem, stick to a low fat diet. The fat in your diet stimulates the gall bladder to release bile which can backflow into the pancreatic duct causing inflammation and pain.
I hope this helps you!

The slow emptying of stomach, called gastroparesis, can aggravate reflux of acid into the esophagus. Best to eat small amounts more frequently and avoid getting overfull from food and gas in stomach. Avoid carbonated beverages and straws (puts gas in stomach). Hot liquids stimulate the stomach to empty. There are Rx meds that promote emptying if you want to discuss this with your doctor.

Thanks so much for the information and support, hoping to start Desmopressin soon, and will start on very low dose to see how it goes. I'm having meeting with dietician this week, hoping to not do low fodmap diet, did that before and it did not help, I've had this for over 2 years, finally getting some deeper dive tests done and found these 2 items. I'm hoping to perhaps find more benign herbal remedy for the gastric emptying maybe herbal, my tests showed liquid slow, but solid not, but that seems to change in real life to solids sometimes also. I just read about the prescription motility drugs, can cause a lot of side effects, I'm super sensitive to meds, so have to take it easy with any of those. Taking thyroid med which is fine and dose figured out pretty much. I was super healthy and fit until 2 years ago got virus, most likely covid, that set off all kinds of metabolic turmoil. Plus I had 5 vaccines so could possibly be that also. Cardiac and thyroid now pretty much under control, now GI and the lack of ADH hormone the issues left to address. The worst is the acid reflux and bloating, along with the pain which may be caused by the refluxing of the acids back into pancreatic duct as you said, so I will definitely try the lower fat and smaller more frequent meals. I lost too much weight last year from being unable to eat much with all the bloating and pain, but thankfully gained most of it back by just making myself eat no matter what. Yesterday I went to an opening party for my Nephew's 4th Tap Room in N Calif, where my brother's band was playing. They have mostly barbecue and tacos menu, I was flummoxed so ended up eating half a pulled pork sandwich with miniscule amt of barbecue sauce. and tiny salad of tomatoes and cucumbers, and had HALF a beer which I haven't had in a year, I actually felt fine, even danced a bit, and slept pretty well, so maybe its not so much what I eat, but how much, and maybe dance after it Ha Ha! Have to remember no matter how awful we feel, must sometimes get out and do things with people and act like a normal person as best you can!