How is the Prophet Muhammad's saying, "And I am the first of the Muslims," interpreted given the existence of Waraqah ibn Nawfal, who believed in the law of Jesus or Moses, peace be upon them?

The Prophet (peace and blessings be upon him) was the first to embrace Islam from his nation, but not the first to embrace Islam among all people, because there were Muslims before him. Waraqa ibn Nawfal was a Christian, not a Muslim. And even if it were assumed that he followed the true religion of Jesus, the law of Muhammad (peace and blessings be upon him) abrogated previous laws. Therefore, the Prophet was the first Muslim of this nation in this regard.