Adding a 30 A connection to my 50 A 2014 Cougar

Some pedestals can handle and some cannot. I wouldn't count on being able to do it.

In case you don't know, that 50a connection actually gives you potentially 100 amps of power. Maybe you just need to plug the heater into a different leg. You might have too many appliances on one leg and nothing on the other. I would be checking my wiring closely before doing that mod that may not be of any benefit.