Is it obligatory to leave one's job if an employee is certain of their manager's corruption and is unable to change it, given the widespread corruption in most institutions and the difficult living conditions?

If the job requires participating with the manager in corruption or assisting him in it, then it is impermissible, and one must leave it if unable to change the wrongdoing. However, if the job itself is permissible and does not involve participating in or assisting with corruption, then one is not required to leave it; rather, one must enjoin what is good and forbid what is evil according to Islamic guidelines.