Closed loop Step Servo Drive Driver 2HSS86H + 4.5N.M Motor + Encoder

[Jonathan]

A Vector drive will give full torque at zero speed, but with an asynchronous motor not a servo or stepper.

Using vector control (also known as, FOC - field oriented control) also gets rated torque to zero speed with synchronous motors. Servo motors are generally permanent magnet synchronous motors and they will use FOC and hence can output rated torque down to zero speed, so long as the motor cooling is sufficient.
Stepper motors are less well defined in their ratings - with FOC they will output some value of torque between zero speed and some value, however this torque value isn't generally quoted in the datasheet, so it is unwise to make a general statement except that this value will be lower than the holding torque.