How does airfoil affect the coefficient of lift vs. AOA slope?
The airfoil affects the lift curve slope only very little; theoretically the slope should be a bit steeper for thicker airfoils.
But that pales in comparison to the effects of wing planform. Here the biggest influence is from the wing's aspect ratio and sweep. Another factor is the flight Mach number and the Reynolds number.
But there is one trick to artificially increase the lift curve slope for a given planform and flight speed: Add a camber flap and move it in sync with angle of attack. This will shift the zero-lift angle inversely to the change in angle of attack. A purely mechanical solution would use a flap with a large control horn, so that $c_{r\alpha}$ becomes positive while $c_{r\eta}$ stays negative. However, this is prone to flutter at higher speeds, so depending on the planned speed range a hydraulic or electric actuator, driven by a control unit which is hooked up to an AoA sensor, might be the better solution.