I wonder if there is a way to optimize the controls to turn left or right (or look left-right-up/down) with keyboard buttons instead of a mouse. I just couldn't find any option in the control menu nor an addon.

To do that, you need a mouse or a controller. Never heard of any other way, at least.

Oh that is not good. I'm kinda tired of just having to play with mouse+keyboard and perhaps a bit of change should add some challange to my playstyle when only playing with keyboard. Mouse is needed huh? hmm

Many thanks for the answer.!

Have you tried a gaming controller ???

That's the easiest way for up-down / left-right...