Detecting step motor effort
I suggest that if the answer involves the Arduino, the question might be appropriate to this forum.

If you can mount your stepper motor in such a manner as to apply pressure to a force sensor, you may have a method to resolve your goal.

As the motor rotates, under normal conditions, pressure on the sensor will give you a baseline on which you can base your program for consideration of the amount of force involved.

Picture the motor mounted in the center of a circle, with cut-outs appropriate for the mounting bolts. On the outside of the circle, you would have suitable bearing surfaces to reduce rotational friction. From the motor circle platform, a lever pressing against a fixed point on the outside of the circle provides the contact points for the pressure sensor.

If you will be rotating the motor in both directions, perhaps a pair of sensors mounted to encase the lever would be suitable.

When the screw is new, clean and lubricated, you can collect pressure readings and establish a safe and comfortable range. Those numbers would be fixed into your code and measured during motor activity.

If the activity results in force outside the range, you can either stop or reverse the motor and have the same checks apply.

The logic and code is beyond my capability, but you'd have very few parameters to examine during operation.