Damp apartment

hello first of all^^

and recently it has been that every morning the windows in our apartment are extremely wet (rather already soaked) the humidity in our apartment is noticeably too high. and that has been the case all summer long.
with the cold outside, the mold has also appeared and is visibly increasing day by day
the mold is currently only forming under the windows and on the windows I believe it is the west side of the house

however, we have only been living in the apartment since April so I can't say how it was before.
we have already talked to the landlord about it and he said there were no problems before.

my question is what could be the reason that the apartment has such high humidity?
it is also the case that this is a multi-family house and the facade was freshly painted not too long ago. could this somehow be related that the outside paint does not let the moisture through.

Do the other tenants of the building have similar problems?

I don't know that
I haven't gotten around to asking her yet
why is that important

If all other tenants had the same problems, this would be an indication that the causes of these high humidity levels are indeed (partly) caused by the building envelope. In the other case, the landlord might suspect that the behavior of a single tenant could be the sole cause of the high humidity.

Have you measured the relative humidity? How high is it? How and how often is ventilation done?

ah ok

no, I couldn't measure the humidity because I don't have the appropriate device for that.
We ventilate by airing the rooms quickly 2 times a day.
And as I already said, the mold only appeared when it got colder outside.

The janitor confirmed to me that the mold is in the entire house and that it spreads every winter, and he has to struggle to eliminate it every year.
It was also confirmed to me that it is a structural cause because the house is not sufficiently insulated at the radiators, which creates a thermal bridge where mold also forms.
Does anyone know about tenancy law because the landlord still claims that we are to blame? Since we are the only tenants in the house because all the other apartments are owner-occupied, we have to take action alone. We do get help from the janitor because he will confirm to the landlord that it is a construction defect.
Because the landlord did not inform us that there is mold in the house, we want to move out again, as we would not have moved in with the knowledge that there is mold.
Can we terminate the lease without notice because of the mold and the false information?
If someone can recommend a site where the exact legal situation is stated, that would be great.