Which of the two supplications is better and more deserving for a Muslim to recite frequently when afflicted by worry: the supplication of Dhul-Nun, "There is no god but You; glory be to You, indeed I was among the wrongdoers," or sending blessings upon the Prophet, "O Allah, bless, grant peace, and bestow Your grace upon our Master Muhammad and upon his family and companions"; so that Allah may suffice him regarding what worries him concerning the affairs of his worldly life and the hereafter? And is supplicating with both of them beneficial for healing from illnesses, especially psychological ones?

It is a divine grace for a servant to confide his worries to his Lord and supplicate Him, especially with the authentic supplications. Both (the supplication of Yunus and the supplication of Ayyub) are suitable for worries. A Muslim can regularly recite whichever of these supplications he prefers, or combine them, and perhaps a present heart with one of them is more potent. There is no objection to supplicating with these prayers for illnesses, especially psychological ailments, as they are types of worries. And there is no objection to taking permissible means by visiting doctors and seeking treatment alongside supplication.