In many cars the navigation display switches to night mode whenever the headlights are on. I have never noticed if the backup camera does the same thing.
Usually if the dimmer for the dashboard lights is moved towards the brightest setting (you may find a detent position at the bright limit), the navigation screen will switch back to daytime mode even though the headlights remain on.
I don't know if your RAV4 has that feature, but you might want to give it a try.
Change the settings in Setup> General to Day Mode, make sure the instrument panel lighting control is in the adjustable section, not full on, must be done at night or cover the light sensor on the left front near the windshield to simulate night time.