White paint is not drying, help needed

Hello, I painted the stairs and ceilings with white lacquer 8 weeks ago. And I moved in 3 weeks ago and haven't been able to get rid of the smell for weeks. I have ventilated often, but it still smells. When I turn up the heating and it gets a bit warmer, the smell gets worse and the ceilings become damp again. What can I do?? Fatigue and nausea occur It's been like this for weeks

Hello, I painted the stairs and ceilings with white lacquer 8 weeks ago. I moved in 3 weeks ago and have not been able to get rid of the smell for weeks. I have aired out many times but it still smells. When I turn up the heating and it gets a bit warmer, the smell gets worse and the ceilings get damp again. What can I do??
Fatigue and nausea occur
Has been like this for weeks

Better ask first, now a professional has to take over. :D