To maximize your productivity, walk as much as humanly possible, as little time in a car as humanly possible.
Ideally, you were able to just do all of your work on an iPhone, whether an iPhone mini or an iPhone SE. To maximize your productivity, the smallest, most lightweight phone is superior for productivity. Why? Less fatigue in your hands and wrists, and also the smaller of the real estate of your phone, The quicker and more efficiently and effectively you could reach all parts of your phone.