I am pretty sure that Ephesians 4:5 is building on the same theme as Ephesians 2:11-22 NASB
11 Therefore remember that formerly you, the Gentiles in the flesh, who are called “Uncircumcision” by the so-called “Circumcision,” which is performed in the flesh by human hands— 12 remember that you were at that time separate from Christ, excluded from the commonwealth of Israel, and strangers to the covenants of promise, having no hope and without God in the world. 13 But now in Christ Jesus you who formerly were far off have been brought near by the blood of Christ. 14 For He Himself is our peace, who made both groups into one and broke down the barrier of the dividing wall, 15 by abolishing in His flesh the enmity, which is the Law of commandments contained in ordinances, so that in Himself He might make the two into one new man, thus establishing peace, 16 and might reconcile them both in one body to God through the cross, by it having put to death the enmity. 17 AND HE CAME AND PREACHED PEACE TO YOU WHO WERE FAR AWAY, AND PEACE TO THOSE WHO WERE NEAR; 18 for through Him we both have our access in one Spirit to the Father. 19 So then you are no longer strangers and aliens, but you are fellow citizens with the saints, and are of God’s household, 20 having been built on the foundation of the apostles and prophets, Christ Jesus Himself being the corner stone, 21 in whom the whole building, being fitted together, is growing into a holy temple in the Lord, 22 in whom you also are being built together into a dwelling of God in the Spirit.
The emphasis on the repetition of 'one' is that there is only one path to God and all are drawn to God by that same path. It is a variation on the theme "the ground is all level at the foot of the cross". Every member of the body is equal because every member of the body of Christ was chosen, saved and redeemed exactly the same way. God paid ALL for each and every sinner redeemed. The exact same Holy Spirit (third person of the triune godhead) sealed every believer as a deposit guaranteeing that Christ would return to claim what was His.
Ephesians 4:5 doesn't make your point, any point that divides based on baptism. Rather it refutes your point. The point of Ephesians ... pretty much all of Ephesians ... is that which unites us is infinite compared to that which might seek to divide us.
Just my 2 cents.