Problem is that the stepper driver is expecting to see 5 volts,
No it is not, I don't think you understand stepping motors.
If the motor says 5V then that combined with the resistance of the coil tells you the current. You do not get this current by applying 5V, you get this current by applying a large voltage, say 24V and using a chopping regulator to limit the average maximum current deliverer.
This over voltage allows the current to get into the coil faster and so the motor develops more toque and so can move faster.
any recommendations for a level shifter that will work fast enough for this?
You need a proper motor driver, not the toy one you appear to have.