I think there’s also a category of rapists who just flat out don’t see their victims as people so they try to take whatever they want if they can get away with it.
It’s still about power since they can only do that to people without power (temporarily due to impairment or permanently due to society).
But it’s not the rapist getting off on having power, it’s the rapist doing whatever they want because someone else has no power to stop them and the rapist has no empathy.