Most dual A/C systems will stagger the compressor start up so one A/C will run cold then the second should run cold, while the first warms slightly. To avoid overloading the power supply.
But it should feel cold 1/2 the time.
Most RVs A/C systems,will struggle to get the inside temps much cooler than 20>25 lower than outside temps.
Shade the windows, start the A/C early in the day.