I'm trying to understand whether the airfoil shape can affect the slope of Cl vs. AOA (coefficient of lift vs. angle of attack) in the "linear" portion, e.g., from a few degrees negative to about 10 degrees. As an example, I picked 9 different airfoils from the NACA 4 and 6 series on airfoiltool.com and they all have pretty much the same slope in their linear regions (Rn 1'000'000):
The question I have is, if I would like a steeper slope (more effect on lift with less change in AOA) are there specific airfoils I should look at? Or any specific airfoil characteristics? Or is this slope basically given by physics for "reasonable overall well-performing" airfoils?