Is the hijab obligatory immediately, or can it be delayed for months to pay off debts and obligations, knowing that not wearing it is due to the employer's condition, and that the husband cannot provide for the financial obligations?

The legal hijab is obligatory for every Muslim woman, and you must wear it immediately. It is not permissible for you to remain in your job if it requires you to abandon the hijab. As for the usurious loan you took, it is haram, and you must repent to Allah. However, you are not required to repay the installments immediately. Therefore, there is no justification for remaining in a job that necessitates removing the hijab under the pretext of repaying the loan.