“According to R’ Schachter and many others, gluten-free oat Matzah is not Halachically bread (or Matzah) and one cannot make Hamotzi and Al Achilas Matzah on it.”
If the gluten free oat matzah isn’t bread or matzah, then oats are not one of the five grains and we can eat oatmeal on Pesach!