Most of the food items you listed are prebiotics(avocado, stevia, buckwheat) and so this is likely upsetting your stomach chemistry. Coconut milk can be problematic from my experience so I wouldn’t consume it, it caused severe gas for me and I had an allergic reaction to it because it was inflammatory.
I would try out some other items such as rice (black, red, wild), oat bran, etc. and see if these are better. You might have to put off having the prebiotics.
If you have IBS then this can make it worse. You could have a different flora that has overgrown such as h.pylori, parasites, strept, etc.
You could lack stomach acid.
There’s too many factors for anyone to diagnose you on the internet.