Is it obligatory for a wife to quit a mixed-gender job, even though she knows that her husband's salary is insufficient to cover their needs, pay the rent, and loan installments?

Borrowing with usury is one of the gravest sins. Mixed-gender work is fundamentally forbidden except out of necessity or pressing need, provided Islamic guidelines are adhered to, such as avoiding private seclusion (khulwa), handshakes, and soft speech, and maintaining hijab (definition), and avoiding mixing as much as possible. The extent of the need to remain in this job must be assessed; if one can do without it, then it is obligatory to leave it. Otherwise, necessity is estimated according to its measure until it ceases.