I just bought my first carbon steel pan. Followed the manufacturers instructions using potatoe peels, salt, and oil. I live in the sticks so I do not have accesss to grape seed or flaxseed oil so I read I could use sunflower oil instead. After that I have cooked a few times only rinsing and a very light rub with a soft sponge then rubbing a light film of oil and heat on the stove until smoke then let cool. I didn’t have many problems at first but now my pan is only darkening in the middle of the pan and my foods are starting to stick there. To try and fix this I followed a chef video that put a millimeter of oil in the bottom heated until smoking swirled it around, drained the oil and let it smoke again then wiped clean and let cool. The outside edge of the pan is incredibly nonstick but the middle is terrible. I am using a glass cook top, which I know is the primary problem because it heats the middle of the element more than the outside. How do I fix this problem?