Flexibility of truck's steering wheel with keyboard
Solution 1:
in settings -> controls section there is "steering sensivity" option - sliding it changes the speed at which in-game wheel is turned - for a gaming steering wheel you set it to maximum(right-most), but for keyboard or gamepad it is useful to lower it.
Solution 2:
I don't believe there is a way to change the keyboard to be less sensitive but you can steer with your mouse which I did find much easier. You can fine tune the mouse turning. Info here