Spinny-dial-based input, with the dial located just behind the shifter (just in front of where the cupholders usually are), is the best input method developed for cars so far.
The forces the UI to be a flat list in terms of navigation (rather than a 2d-space-filling UX mess). And being a flat 1d list, it encourages the list be short, which means more submenus, which is good!
If menus are consistent, you can mostly control without taking your eyes off the road.
Apple CarPlay already works with this input method.