For ages I used to suffer from very sharp cutting like pains across my tummy. Ultrasound, barium meal & endoscopy & they found slight reflux, no ulcer & a little scaring. What they did discover was I overproduced acid. No food in my tummy - pain. Not from hunger but from too much acid. The pain & the acidic tummy often made me not want to eat but, you know, vicious circle. The easiest & quickest way to stop the pain was to eat. (Carbs like bread, cracker breads, pasta, rice, etc. worked best - more absorptive I guess.) Because much of this is like what you’re experiencing I wonder if that is your problem too. Certainly worth asking your doctors.
I take Nexium every day now. I say it’s for my increased but different reflux but I also think a lot of it is still too much acid in my tummy. And it’s likely why, & with no gall either, I have random attacks of diarrhoea a couple of times a month - acid irritating my bowel.
Changing your diet is a great start I managed my reflux that way after it was diagnosed. Only took esomeprazole occasionally then. No carbonated drinks (terrible hiccups if I indulged in more than 2 glasses of champagne or G&Ts), no spicy food, nothing too fatty, no rich or creamy foods (watch cheese too), reduced caffeine (single large mug of green tea a day).
Maybe try eating more regularly & more dense food (not advocating lots of simple carbs but maybe some good complex whole or multi grains).
I hope they can find an answer for you soon. All the best.