Is it permissible to use a false certificate of experience to obtain a job, and is the salary acquired through it considered ill-gotten gain, especially given the necessity of lying when asked about it during the interview?

It is not permissible to submit a fake certificate of experience to obtain a job, because that is considered forgery and deception. Allah the Almighty said: "And avoid false statement." And the Messenger of Allah, peace and blessings be upon him, said: "Shall I not inform you about the greatest of the great sins?... and false statement and false testimony." And he, peace and blessings be upon him, said: "Whoever deceives is not of us." The difficulty of obtaining a job or family pressures do not justify that. And whoever gives up something for the sake of Allah, Allah will compensate him with something better than it, as stated in the hadith: "Indeed, you will not give up anything for the sake of Allah, the Mighty and Sublime, except that Allah will replace it with something better for you than it."