Automatically Lighting Lamp on Shabbat

Hello, we recently moved from Bnei Brak to abroad. In the building we live in, there is a lamp that automatically turns on when entering the building. We didn't notice this during the visit because it doesn't turn on during daylight. We understood that there is a leniency in adding a lamp that is always on, so we do not benefit from the automatically lighting lamp. Can we rely on this leniency, or is it better to decide to pray at home on Friday night? Question B: In the morning, it is unclear when the lamp turns on and when it doesn't. It seems to depend on the amount of light entering the building at that time, according to the hour and weather. Does this ease the permission for Shabbat morning or at sunset, or is it still forbidden to pass out of doubt, and one must wait for a time when it certainly won't turn on? Our desire is to move to another place of residence as soon as possible, but the conditions for obtaining an apartment are not easy, and it may take a long time. Best regards.