Salvation by water baptism is NOT the gospel. Water baptism is merely the picture, but is not the reality. The gospel is the "good news" of the death, burial and resurrection of Christ (1 Corinthians 15:1-4) and is the power of God unto salvation to everyone that BELIEVES.. (Romans 1:16).
There is only one gospel- the gospel of Jesus Christ- which is the good news of how the death, burial, and resurrection of Jesus Christ can save us from hell if obeyed. During baptism we die to ourself, bury our sinful self in the watery grave of baptism, and are raised a new creature in Christ- that is the one and only gospel that saves.
Romans 6:3, 1 Peter 3:21, 2 Thesalonians 1:8, 1 Corinthians 15:4, Galatians 1:8
*To believe the gospel is to trust in the death, burial and resurrection of Christ as the ALL-sufficient means of your salvation. We obey the gospel by choosing to believe the gospel. Romans 10:16 - But they have not all obeyed the gospel. For Isaiah says, "Lord, who has believed our report?
The gospel is a message of grace to be received through faith. The gospel is not a set of rituals to perform, a code of laws to be obeyed or a check list of good works (including water baptism) to accomplish as a prerequisite for salvation. You are unable to see anything beyond your church of Christ indoctrination.