No factual error here. The wheat flour from which I make bread has 13% proteins, while the cornflour that I use has 6.4% proteins.
It is likely that unlike me, you do not cook your own food, which is why you are not aware about the content of nutrients in food ingredients.
The protein content in other parts of plants does not matter. Only the content in the products that you can buy and use for cooking matters. The 6.4% protein content for cornflour is pretty much the same in all brands of cornflour that I have seen in Europe. The wheat flour that I use is the one with the highest protein content. Most other brands have a lower protein content, down to 10% of protein.
> Corn / maize: less than 17 grams carbs per 100 grams
This must be a hallucination. Cornflour almost always has around 75 grams of starch per 100 grams. Wheat flour has a slightly lower starch content, the value written by you, 71 g per 100 g is indeed correct and typical.
The energy content of the cornflour I use is 3410 kcal/100 g and of the wheat flour is 3530 kcal/100 g. Nevertheless, the slightly higher value for wheat flour is misleading, because the gluten is never digested completely and even for the part of the gluten that is digested, the body spends more energy for amino-acid processing than for starch processing, so the net energy intake is actually slightly lower for wheat flour.
It is possible to eat only fat for energy. It is also possible to eat only carbohydrates for energy. This does not mean that the extremes are the best choices.
So you should better check your facts, because the values are so far from correct as to qualify for "hallucinations" (i.e. "more than three times" vs. 13/6.4 and 17 g vs. 75 g).