Ok, assuming the sandwich has a length of 1 and the bread is perfectly square, we can determine which cut has more through the area of the sandwich’s.
Cutting it diagonally would result in of 1/2sandwich^2 per sandwich piece through 1/2(base)(height) being the area.
The rectangle cuts would also be 1/2sandwich^2 per piece through the formula (base)(height) meaning that no, one doesn’t have more area than the other
