Is it permissible to benefit from the money I received from the state during my unemployment, knowing that this money is not rightfully mine, by using it to search for a job and pay my rent, and then donating it later?

This money is not rightfully yours, as it is a wage not earned by work. However, if the institution's director was aware of your absence and was authorized to grant you the salary, and did not terminate the contract, then this salary is considered a permissible gift to you. If it is not rightfully yours, then you must dispose of it by spending it on general Muslim welfare or on the poor and needy. If you are in need of the money to search for a job, there is no objection to benefiting from it, as Al-Ghazali stated that it is permissible for the poor person to give unlawful money in charity to himself and his dependents. It is more appropriate for you to give this money in charity for general Muslim welfare if you become well-off. It is permissible to benefit from it if it is public money whose owner is unknown. However, if its owner is known, it must be returned to them.