Did you try cutting out 'enriched' flour? That seems to be a major trigger of heartburn for me and I do a lot better without it.
Raw or whole foods are a few orders of magnitude more gentle on my stomach than foods that are engineered to be shelf stable for months at room temp in the pantry.
A whole other chapter of filth, those.-
We are, mostly, unwittingly poisoning ourselves for the purposes of keeping a given food-industrial supply chain going.-
Which also works, I guess