Is it permissible for an employee who has been arbitrarily dismissed in a Gulf country to demand their full end-of-service benefits according to the country's law, and compensation for the material and moral damages resulting from the dismissal, in addition to the legally stipulated increase for each month of delay in the event of the employer's intransigence?

As long as you willingly accepted the conditions stipulated in your specific employment contract, the default is that you must adhere to them, and you do not have the right to demand anything contrary, even if labor law grants you more rights than those specified; for the condition stipulated in the private contract is stronger than general custom. It is not permissible to resort to deceit to obtain a right in place of a betrayal, as Sheikh al-Islam Ibn Taymiyyah mentioned. Therefore, he has no right due from this company except what is contained in the contract.