To install an energy management system where there's never been one would require extensive rewiring of the RV breaker panel. Intellitic
made EMS systems installed in many 30 amp RVs with 2 A/C, but with the more common 50 amp service and it's almost 3 X the amperage available over a 30 amp system, I don't see one listed from them anymore.
Replacement boards for the Intellitec EMS run ~$300-$430 and a replacement display is over $100. Generator / Transfer Switches / Surge Guards / Energy Management Systems | pdxrvwholesale
A 30 amp to 50 amp conversion would require a new power panel and new circuit breakers unless you install a compatible panel that would allow the reuse of some of the old breakers. If you have an automatic transfer switch, it would also need replacing with a 50 amp one and a new shore cord. Extensive rewiring would also have to be done, although much of the wires in place could be used. Just parts alone would run $500-$800.
I really don't understand your reluctance to use a 20 amp cord for the second A/C. The campground pedestal should be able to handle the 30 amp shore cord and the additional 20 amp cord. Neither would be using the maximum CB rated amps, so less than 50 amps total. A 50 amp outlet has the capacity to provide 100 amps at 120 v, the capacity of an RV 50 amp outlet.