I don't understand why you are passing enough current that the motors and wiring are getting hot.
I am using 2 Nema 17 steppers on Ra/Dec and an Nema 11 for Focuser on my MaxESP3 setup.
They have been continuously powered up on the bench for 3 weeks and its difficult to tell that they
have increased in temperature from ambient. In fact holding one that is disconnected in one hand
and a connected one in the other hand they are so close to the ambient temperature of the room
that I totally disregard the setup as far as the curent is concerned. I suppose that I could measure
the temperature rise for youThey work as they should and have given not one second of trouble.