Don't make a science out of it: you are additionally moistening the air:
With an extra humidifier (Venta) we reach just under 40%.
But you expect the controlled residential ventilation to quickly ventilate out this additional humidification before it condenses on surfaces with dew point undershoot? A local electronic room humidifier regulates very ... digitally, if it measures too low, it briefly increases to 60%+ in the immediate vicinity and expects that it will then mix to 40% throughout the entire room. In practice, that doesn't work: the rain cloud from the humidifier drifts along the natural circulation toward the ceiling and falls back down along the windows, where it can nicely condense.
How warm is it at night in the rooms with condensation? If you absolutely want to maintain 40% humidity, then you also have to ensure that the necessary room temperature is maintained, so around the clock at least 22°+