I really like the question, thank you! The answer is a clear “yes, but”:

Your assumption is absolutely correct, light surfaces reflect more light back and heat up less because of this.

Noe if your display heats up less depends on the amount of energy it uses to generate that white:

For an e ink display it would be basically the same as a bright vs dark paper of the same color. But OLED for example uses constant energy to generate the white image: So it’s depending on how bright the sun shines vs how much heat gets generated by the display itself.

Still only looking at the sun’s energy it would be smaller. If the overall temperature would be lower depends on exactly how bright the sun would be vs how efficient the specific display is!