Can a workplace be a source of ill omen and distress, and is the decision to leave school due to repeated failures to complete marriage proposals correct, especially since the matter has not yet become clear after performing Salatul-Istikhara?

The failure of an engagement or marriage is a trial from Allah. It should not be linked to attending a specific school, as that is a form of tatayyur (superstitious belief in omens) and tashā’um (pessimism), which are forbidden in Islam and contradict Tawhid (definition) (monotheism). Tatayyur involves refraining from an action or proceeding with it with anxiety and apprehension. If one's heart is not at ease with remaining in the school, there is no harm in leaving it after seeking counsel and performing Istikhara (prayer for guidance), and considering what is in one's best interest.