I would like to set a certain key to a partial amount of throttle (e.g. "v" key throttles at 50%). This would be really convenient when i dont have remote
You can use your mouse instead to control the throttle and/or steering. A controller is highly suggested, as keyboard as its own limitation as you see.
that can slightly be done if you get a wheel, controller or joystick. but yeah that's a good idea man