I know of major Poskim who are Mattir Kitniyos for those with (real) gluten allergies/
I developed some crazy food sensitivities in the last years and gluten (or flour?) gives me terrible headaches and literally puts me to sleep. I had the same reaction, for some reason, to gluten free oat matzo. I couldn’t figure out why my head hurt when i was eating non-gebrocts pesach food til i deduced that potatoes is also a problem. I can eat yogurt but when i ate cheese for lunch I was in much pain.
while it pains me so much not to have anything to eat for the mitzvah of matza, or for most of the meals, i could not see myself eating kitniyos on Pesach. Id rather be hungry (which, by the way, i am).