A 2 ohm stepper motor is a low impedance stepper - use current control for these, basically any
stepper chopper-driver that can handle 1.2A, such as DRV8825 module.
Most steppers these days are low impedance, and are completely unsuitable for any constant voltage driver
like standard DC motor drivers.
Years ago high-impedance steppers were more common and hence why many dual DC motor drivers
claim to drive a stepper - these days that's misleading.