Is it permissible to delay wearing the hijab for fear of losing one's job, and how can one atone for past sins and transgressions?

It is recommended to repent and do many good deeds. Allah Almighty says: "But whoever repents after his wrongdoing and makes amends, indeed, Allah will accept his repentance. Indeed, Allah is Forgiving and Merciful." It is not permissible to remove the hijab for a worldly purpose, because Allah has made the righteousness of this world and the hereafter dependent on His obedience, and sins are a cause of deprivation of sustenance. As for the fiancé: If the marriage contract has been concluded, then there is no sin upon you for what he received from you, because you are his wife. However, intercourse is not permissible during the daytime in Ramadan, while kissing, embracing, and similar acts have an effect on the fast. If the marriage contract has not been concluded, then sitting with him, being alone with him, and anything beyond that are all forbidden, and you must repent to Allah.