Your level of hubris is astonishing. Your lack of technical skills is somehow exceeded by your lack of people skills. You demand people to keep explaining to you why something won't work when it has been explained over and over. And you have zero shame re-asking the same question that you should have learned either in Physics or in one of your engineering classes. This is not advanced at all.
Your fixed unit is watts. The watt is a common unit of energy. It can be expressed in other units but, that's what you have.
You're proposing taking a fixed number of watts and putting them into a motor. That motor converts watts into mechanical energy (Horsepower if you like, though the unit conversion isn't important). From the motor shaft, it moves to a generator and turns back into electrical energy (back to Watts). The voltages are meaningless in this system.
In a perfect system, the watts would remain fixed: neither gaining, nor losing energy. Double the volts and the amps are half. Watts remain the same.
Any heat lost anywhere in this system is lost watts. If it loses anything to friction, you will measure less watts than you put in. If the windings get warm, you have less watts than you put in.
Double the volts is just half the amps. It does not make more watts.