If you want to apply paint or wax as quick as possible you’d struggle to beat Airless Spraying.
Airless spray equipment atomizes coatings by forcing high-pressure paint through a small nozzle without using compressed air. A pump pressurizes the paint (typically 1,500–3,000 PSI) and pushes it through the spray gun. As the high-pressure stream exits, it expands rapidly, breaking into tiny droplets for a smooth, even coating.