As you make a symmetrical airfoil thicker, in which direction does the lift force increase?
Lift is defined as the vector component of the total aerodynamic force perpendicular to the freestream velocity vector. Wikipedia about lift

By definition lift can not contribute to thrust or drag, so the direction is fixed.

The sense of the lift vector is opposite to the flow deflection caused by the angle of attack, so the lift increases in that sense.

For your project you might be interested in looking at the lift/drag profile, rather than just at lift.