I have had GERD since I was in junior high, and I am in my 40s now. I have tried several medications, but they all had side effects that I couldn't live with or just didn't even work. I have had multiple upper GI scans and developed diverticulitis before I was 40
I haven't been diagnosed with a hiatal hernia, but that is what I suspect I have. The 2 things that improved mine the most were taking allergy medicine, ie antihistamines/decongestants, and a paleo/ketogenic diet with primarily meat, chicken, fish, and vegetables. I would also recommend just not eating all of your food, especially if you are eating multiple meals. Restaurants serve big portions. I like to try to stop after eating about half and wait about 5 or 10 minutes to see how I feel. Also, if you aren't hungry, just don't eat. Skipping a meal or two won't hurt.
I didn't realize for a long time that I even had allergy issues. Once I started taking medication to reduce drainage it helped a lot. Mucus is really hard to digest and causes a lot of acid production. My allergy drainage goes right down to my stomach. Not everyone has this issue though.
I never started eating paleo/keto to help with my allergies or stomach problems. I just wanted to lose some weight and fat. I was shocked when I found I could eat things that would normally bother me, like fatty/greasy meat or gas producing vegetables like cucumbers and onions. Vinegary or acid sauces used to bother me too, but not really anymore. It can take a few weeks or a month for the effects to kick in, but I love how it feels. I found I could eat more food too. I guess the bready carbs and sugar just weren't being digested well and were sitting there. I have also cut out most dairy, except cheese as part of an occasional meal or salad. I started out using the Whole 30 Diet but have gone to a little less carbs, ie no fruit, for more fat loss and to help kick my sugar addiction more. So, your theory about GERD and gluten is probably not far off, because paleo/keto diets tend to be almost gluten free.
From that point of view, I would think places with salads and protein/veggie dishes would be good. I haven't eaten there, but Satu'li seems to fit that bill. I really liked the sustainable fish at Skipper Canteen, the chicken, broccoli, peppercorn salad at Columbia Harbor House, the sustainable fish at 50s Prime Time. Taco salads are a good choice; I just don't eat the tortilla. Fajitas can also be good; again, don't eat the tortillas. I have even been known to eat the hamburger patty and toppings without eating the bun. You can do the same with chicken sandwiches.
Good luck. I hope you find something that works for you. I know it can be very miserable. I suffered, probably what was needlessly, for more than 20 years. Eating paleo/keto is not for everyone, especially if you love sweets. However, I highly recommend that you give it try, especially the Whole 30 Diet for the entire 30 days. I wouldn't try to be strict about it while on vacation, but when you are home, try to really stick to it for 30 days and see how you feel. I had gotten to the point that I felt I had nothing to lose, so 30 days was not much to try it. I was just really surprised how good I felt and feeling better was not my intention to start with.
