The next bit's not quite right ..
the prop drag will be much lesser than the engine torque
We can't equate the two as they are are different - drag is a force while torque is like a moment. Better to say that the engine torque can provide the means to
(a) allow the prop to slow down (engine torque less than what is required to balance the prop disc drag loads so the prop decelerates until the drag loads are balanced by the engine torque)
(b) maintain an RPM (engine torque equals what is required to balance the prop disc drag loads)
(c) cause the prop to accelerate (engine torque greater than what is required to balance the prop disc drag loads so the prop accelerates until the drag loads are balanced by the engine torque)
Oh..That makes a lot of sense.
Thank you!
Sorry for the amateur questions and conclusions!!