If your existing 30 amp shore cable is the proper 10/3 type cable, you are not "dropping" or losing a significant amount of power with a 30 amp load.
Upgrading to 50 amps would let you run a bigger A/C (a 240 volt model for example), or run multiple A/C at the same time and still have power left over for microwave, etc.
30 amp service is 30 amps all on one "circuit" so to speak, a single pole.
50 amp service is 50 amps + 50 amps on two circuits, or double pole. So a 50 amp connection actually gives you 100 amps to play with for 120 volt loads (spread across the two 50 amp circuits) or 50 amps for 240 volt loads.
it makes sense that the EMS would be disabled in 50 amp mode, with 100 amps to work with, there's little reason to shed loads.
edit:
I should have started with this ... upgrading your electrical service alone will not help your existing A/C cool any better
2013 KZ Sportsmen Classic 200, 20 ft TT
2020 RAM 1500, 5.7 4x4, 8 speed