Is breaking off an engagement due to the fiancé's work in a bank a punishment from Allah, especially since the Istikhara prayer was performed multiple times?

The believing woman must be content with Allah's decree, for all the affairs of a believer are good. If the young man worked in an interest-based bank, then Allah turning him away from you was a blessing, for Allah chose what was best for you as a result of your Istikhara, and it is a beneficial trial. You erred by accepting him, because religion and character are the foundation. Praise Allah Almighty for this blessing, for Allah averts evil from His servant out of His mercy. Failure once does not mean perpetual failure; rather, let what happened be a motivation to choose a righteous husband of good religion and character.