If you are you flying with all
your engines out, you are a glider, it does not matter what kind of engines you
had. The airframe is the only consideration, so you will get max range at VMD
and max endurance at VMP.
The only reason there is a difference between FLYING for range and endurance in
jets and piston props is because you have to make some sacrifices to accommodate
the performance of the engines.
With a piston prop, the engines produce power, the propeller converts that into
thrust, there is already a huge loss of efficiency, so
the airframe becomes the most important consideration. Therefore range stays
VMD and endurance VMP.
With a jet, the engine is very inefficient at low speeds so we sacrifice some
drag to make the engine more efficient for both range and endurance, so the
speeds will be faster than a piston prop. Therefore best
range at best EAS/D (1.32VMD) speed and endurance at VMD.