Is this phrase established from the Prophet (peace and blessings be upon him): "The best of kings is Mu'awiyah"?

Question:
May Allah reward you, Honorable Shaykh. This questioner asks: Is this phrase established from the Prophet (peace and blessings be upon him): "The best of kings is Mu'awiyah"?

Answer:
Allah knows best. I do not know. Mu'awiyah was a Companion (may Allah be pleased with him), and that is sufficient for him: that he was a Companion among the Companions of the Messenger of Allah (peace and blessings be upon him), and that he was the son-in-law of the Messenger (peace and blessings be upon him), for his sister Umm Habibah was a wife of the Messenger of Allah (peace and blessings be upon him). He was also the scribe of the revelation, writing the revelation for the Messenger of Allah (peace and blessings be upon him). He has great virtues (may Allah be pleased with him).
And it is sufficient for him in terms of virtue that Allah united the Muslims through his hand, suppressed the fitnah (trial, discord or temptation) through his hand, and his caliphate and his authority (may Allah be pleased with him) were the greatest in uniting the Muslims, extinguishing the fitnah, and putting an end to the people of fitnah, and he governed the Muslims with good governance.
And Allah granted him forbearance, mercy, and strength, so he has virtues (may Allah be pleased with him). Yes.