The story of Naaman to illustrate your doctrine is invalid. Naaman had to dip 7 times for physical healing, not for spiritual salvation, forgiveness of sins, the new birth, or eternal life. The New Testament does not use this story as a type of a checklist necessary to receive salvation. Naaman was obeying one command (wash in the Jordan) repeated 7 times. Your doctrine requires obeying 4 separate commands (repent - believe - confess - baptize). There's no parallel between what Naaman did to be physically healed, compared to salvation.
Naaman was healed by God because of his humble obedience, not because he dipped 7 times in the Jordan river. God could have told him to throw 50 rocks, and if he obeyed, he would be healed.
Nowhere in Scripture do we read, "If you repent, believe, and confess, but skip baptism, you're not saved - like Naaman after only 6 dips. Again, there's no valid parallel between the two.
Baptism is not one mandatory "dip" in a multi-step salvation formula.
You're trying to fit your doctrine into an Old Testament story, and then calling that an illustration of New Testament "truth". The Old Testament story of Naaman is not a blueprint for a New testament "plan of salvation."
The clearest New Testament teaching on how we are saved is STILL: Believe in the Lord Jesus, and you will be saved - Acts 16:31
Then, have been cleansed of your sins, having received the indwelling Holy Spirit, as an act of joyful obedience, be baptized.