To safe battery life I have done some research and the outcome was than on devices with OLED screens, black pixels are turned off, which means that using a black or dark theme I can save battery life. Therefore, a black home screen and desktop would be more battery-efficient and on devices with LCD screens, the backlight is always on, regardless of the color displayed. In this case, the difference in battery consumption between a black and white background is negligible.... if dark mode is only for optical reason and not for energy /battery life I would not choose dark mode (when LCD display)