It's a common misconception that different ways of connecting and/or driving coils can emulate a CVT, multi-speed gearbox or single speed gear reduction. The maximum continuous torque of a motor is purely a function of the maximum continuous airgap shear stress, which itself is a function of flux density and current density. Doesn't matter how you connect or drive the stator coils, you are always limited by the current density in the windings.