Most of the things you cite, like phones, cars, airtags, can already be powered just off batteries and the electric grid, so the actual source of the energy is already abstracted away.

A large-scale nuclear plant will be way more efficient than a bunch of mini-plants, so having battery electric cars + nuclear power plants already gives you nuclear powered cars without even having to invent anything new.

We only need to focus on fuel generation (power plants), and the small number of remaining places that don't just take power from the grid (planes, ships, other things that have their own fuel/generator on board).