There was (at least one) very long thread on this topic with discussion about using the cupholder for phone placement, as well as links to the best uber-engineered mounts on the market. If you can find it.....else scan back through my post history as I posted a comment in that thread (quite a while back).
eta: here's one I was looking at recently https://www.cobbtuning.com/brands/scosche
eta: here's one I was looking at recently https://www.cobbtuning.com/brands/scosche