EL7041 with stepper NEMA17

There is only one setting. That's the current.
If it is getting hot then the current is high

I guess that the driver could be using such a low PWM rate that the torque dips low enough to slip, but that would be a broken drive,

Have you ever run the stepper with much to high current?
It is possible to demagnetize a motor that way and then you endup with no force!