When you put the car in the reverse and the rear camera activates, press the camera icon at the bottom of the screen. What happens when you do that? In my 2019 RRS ATB, when I press the camera button it toggles between the regular rear view camera, and a view that shows the rear camera, the 360 camera, and the parking sensors.
You need to make sure you have the 360 camera enabled from the camera settings. At the main screen, press the camera button, then settings, then camera settings. Press the button next to "Default Camera View Selection" and make sure the 360 camera is enabled as an additional view when forward/reverse gears are selected. Then the camera toggle I mentioned above will work.