If you’re going to use it as a screwdriver you’re going to have “torque problems”. Either you’ll run out of torque, the motor will “slip” and you’ll loose count of the steps, or if the motor is big enough you’ll strip the screw.
Agreed. This is a major issue. And the amount of torque needed may vary even between apparently identical screws.
If the motor has too little torque the whole idea is pointless.
If it has the essential excess of torque then you are relying on it stopping after the required number of turns and before any damage is done. Can you determine the correct number of turns?
I guess you could have a slipping clutch that was set at a higher torque than is needed to drive the screw but which is still low enough to prevent damage. But determining that setting might not be easy.
To my mind a traditional DC motor with a suitable clutch makes a lot more sense. You could mount a rotary encoder on a regular screwdriver so you could measure how far it turned.