The Unpopular Opinionator has not converted to Roman Catholicism--not yet anyway. However, I've never been closer to Rome than at the present.
Jesus' Messianic office is both a spiritual and a political office. His Ascension to rule over all things was an inheritance granted once he completed his earthly course of obedience, proving to be simultaneously the faithful Israelite, the faithful son of Adam, and the faithful Son of God.
The Son does not rule according to his divinity over creation by a "providential" reign and as man over a "redemptive" realm. The sphere of redemption encompasses the whole cosmos already, though manifested but partially in the present. We are living in the Age of Faith after all!
The Two Kingdoms conception of Christ's rule is an error derived from a faulty hermeneutical principle, the Law-Gospel distinction. Entirely absent from Scripture is a covenant of pure law. Likewise, a simple promissory covenant is nowhere to be found. Every biblical covenant is qualified by conditions of obedience. Luther was wrong.
The glory of the New Covenant is not that God removed the requirement of obedience as a condition to inherit eternal life. The glory of this new and better covenant is that it imparts the power to obey to all those who trust in Jesus' atoning sacrifice.
What is true for all men, everywhere & at all times, is that if they would come to God they must believe that He is and that He is a rewarder of those who diligently seek Him.
Jesus is Lord.