Yea, it's a "Catch 22" going on in so many of our RV's when it comes to condensation. You do something to improve a situation, but it causes problems in another area.
I would think if you want to help insulate the vents in the ceiling, put a cover on them outside the camper. See if that would help and reduce the condensation.
A simple trash bag spread over the vent and held down with a few small bricks or heavy rocks is probably all you would need to do. You might try that and see if reduces the condensation INSIDE the camper.
Who you are right now is a sum total off all you use to be.
2019 Montana High Country 375FL
2014 Chevy Silverado Duramax, 6.6L Dually