One Shot is an alternative ESC (Electronic Speed Controller) it is faster basically. It sends “one shot” of the signal every flight controller loop, and it does this as soon as the Flight Controller has a new value for the ESC. (I am guessing maybe this why it’s called “oneshot” ). It waits for a change before firing another "shot"
You still need some kind of ESC, even if it is a One Shot style. No way will the puny signals from the Flight Controller fire up a motor, and in any case the ESC must convert PWM signals to three wire motor drive (normally). ESCs assume an electric brushless motor. You can deliver a KW to a high power motor with a big enough ESC. You have said nothing about how you intend to drive your motors - what "alternative power supply" they use. If other than a brushless motor, you may need to invent your own Speed Controller, and examine the One-Shot or PWM ESCs to see how to convert.
I would go with QGroundControl, but I may be biased. Others would say Mission Planner. In truth either is flexible enough for your needs.