How sound is the attribution of this prayer upon the Prophet (peace and blessings be upon him) and its reward to him? Did he inform us about it, or should it not be attributed to him?

The aforementioned Hadith has no origin in the books of Sunnah, nor has anyone narrated it. Signs of fabrication are evident in it, as its wording is weak, and it contains false meanings that contradict Islamic law, such as the allowance of forbidden amulets, and its statement, "He will be rewarded with the merit of four angels and four prophets." Angels and prophets are the best of Allah's creation, and no one can resemble them in their reward and ranks. What has been authentically established in the sound Hadiths regarding forms of prayers upon the Prophet (peace be upon him) suffices over anything else.