There are many bugs on the wall of the room.

If you ask me, it's best to spray insecticide first, and then play with latex paint (it's best to find a professional for this job). In fact, the root of this problem is the bad wall. You should find a company to decorate it for you Their wall materials are not up to standard, or you didn't do gable insulation, or the temperature difference between inside and outside is big and humid. There are many reasons. Your one-way method is still the one I said.