I also watched that video and it makes sense. I'm not in extreme heat so it's not something I'm going to do but when replacing my AC unit I found two things which probably helped my system a lot. One issue was the loose divider baffle between the warm and cold sides and the tubes where they connect to the duct vents letting cool air into the roof cavity.
On my old girl I figured it was mainly age related but the more you look at RV construction it would be easy to believe they come from the factory that way.