Would a 100k ohm resistor or motor emit more heat
100k is a very high resistance for a motor ..

The resistor will get hotter, because as you say the motor is transferring energy somewhere else. If you put the motor plus whatever it's driving in a sealed calorimeter, and don't have it driving an energy store (winding up a spring, lifting a weight etc), then the total heat rise in the calorimeter will equal the energy put into the system.