I can't share any helpful info to a lot of your stuff, sorry. I do have issues with acid reflux but that's because of a biological anomaly I have (the valve that connects my stomach to my esophagus doesn't work right). I find that eating more red meat helps anemia and asthma issues, but I cannot eat too much of it in one sitting or I get acid reflux. Snacking multiple, smaller meals throughout the day has helped me the most with my reflux. This might make your reflux worse though, everyone's body is different, but maybe meal portions are something to experiment with.

(It's difficult to have animal products aside from cheese ready to go for snacking though so the best options for me are like, prosciutto with cheese snacks or saving meat options for my main meals and then my carb/fiber intake with snacks. Cheese does make me phlegm-y though so if that happens to you, maybe lean more heavily into deli meats.)

Making some lifestyle changes too. I mostly have reflux at night when laying down, especially after a large dinner. So I try to eat heavier meals in the morning/early afternoon and have a light dinner, I try to sleep at an incline (look for a bed wedge pillow), I try to avoid spicy/acidic foods for dinner, etc. You seem to have all of that covered though, so I'm not sure what else there could be to do other than experimenting with diet.

I also grind my teeth a lot and it is absolutely worth investing in a mouth guard. This is something I have always had an issue with, unrelated (to my knowledge) to diet. Your dentist may be able to make you a hard one that can last for years, it may be worth asking about. I go to a dental school instead of a dental practice so everything I get is heavily discounted, but mine cost me like $200.