How accurate is the statement that Muslims will not unite until the Seal of the Prophet, peace and blessings be upon him, which was lost by Uthman, may Allah be pleased with him, is found?

Ibn Hajar, in Fath al-Bari, mentioned a statement implying that there was a secret in the Prophet's ring, just as there was in the ring of Solomon (peace be upon him). The dominion of Solomon was lost when he lost his ring. And when Uthman lost the Prophet's ring, his authority was disrupted, and the discord began, leading to his assassination and continuing thereafter.