Electrical braking a stepper motor (revisited)
Torque is controlled by current and the velocity that creates the BEMF is not sufficient to add much torque compared to say 25% PWM or even less with a light bias force. But it will retard an impulse disturbance, yet not a slow drag.

if you are using microstepping, i suggest it is better to use full stepping with a pulley gear reduction on load torque effects then use acceleration and velocity control to increase your seek time and reduce your voltage to manage energy consumption.
can this be done in your software or controller Zaxis gcode driver to regulate PWM ? Is it hard to do simply, perhaps but that depends on your system.

If you can monitor slip voltage from the open circuit gated logic , you may be able to integrate the current in a burden R and reverse it for short disturbances before it slips a step. But this is getting fancy.

your best bet is to balance the forces so there is less chance to slip or get a different servo motor that does it automatically with rotor feedback.