I tried to PM about this issue but I'm not sure you got it. Here is the short:
I have similar issues but the whey hydrolosate in Surge treats me fine. I have used it for a while with no issue and have recently even increased my intake to 2 servings.
I also use a waxy maize, L-luecine mix. I have tried oatmeal starch and BCAA. I can take egg protein but tend to use that for additional meals, not para training. I have a rice protein. Gemma protein messed my stomach up worse than whey. Beef isolate also caused digestive issues. Send me a PM if you want specific brands. I like Biotest and feel it a bit unethical to promote other companies' products on their forum. Call it principle.
Although nutrition protocol isn't as easy for us as others, there are options out there.