Faulty formulation: The Messenger ﷺ had a universal mission, but another prophet may still come after him.
Correct formulation: Both the universality of his mission and the finality of prophethood are affirmed. He ﷺ was sent to all humanity, and no prophet will come after him.
وَخَاتَمَ النَّبِيِّينَ
And he is the Seal of the Prophets.
Application: The two propositions must not be set against each other. A message for all humanity and the closure of prophethood are distinct but compatible beliefs.