I'm still figuring out the right microphone settings with this camera and my two microphones. It will improve as I learn what levels do and don't work.
You have to set your camera's output settings to 4k60p as well as the settings on the Ninja V. If you check your camera's manual and the Ninja V documentation it says how to do it. If you have an A7SIII Gerald Undone did a good video showing how to set it up as well.