Turn off the screen while using Maps

Hello to all :)

I'm writing this post because I'm wondering if the behavior of my iPhone 8 Plus is normal. While using the Apple Maps app, during navigation, when I turn off my screen (by pressing the power button), the screen turns off and then turns back on at the next instruction (so far so good).

The problem is that after this guidance instruction, the screen stays on; whereas I would like it to turn off again. This would save the battery in a consistent way.

Does your iPhone act the same way? Is there a way to make it act differently?

Thank you for your answer