But if you look behind yourself your head is pointing away from the screen.
Not necessarily if you've got a curved ultra-wide display. Combine this with some rotation factor and you can look around while still looking at the screen.
It's not a 1:1 link with these, turning your head only slightly is enough to look behind in game.
Typically people don’t use 1:1 movement when using something like this. It’s a much higher ratio so you only have to slightly move your head to look around. It allows you to do it quicker but also avoids exactly what you’re describing.