I found that it's possible to relax and hold the wheel in a different way. If I relax my shoulders, my arms, forearms, and just let the hands fall into the wheel, then my grip actually tightens. The weight of my arms pulls them into tightening my grip without any strength being applied.
It helps if the wheel is not too slick, on mine it has stitching which I can get more friction off. So, I relax my whole arms, and so my pectoral girdle is more relaxed. I am less tense in the neck, less prone to numbness down the radial and ulnar nerves.
But there is more to it still, when I turn the wheel I am more aware of how a turn to the right pulls my right hand down and my left hand up, . I am more aware that I can turn the wheel either by pulling down, or by pushing up. I am more aware that I can do either or both by moving my centre into the arms. I feel the car more. Feel the road more, feel the turns more. I cant say that I can outreach right through the the tarmac but you get the idea.
It's a similar thing with the pedals, I can press them not with my foot but with my body. I can change gear more smoothly by moving from the centre.
It's an interesting experiment to play with. I suggest that you do it only at your own risk, but my experience is that it actually improves my driving and my awareness of the road.