I can only tell you what my fellowship believes, teaches and confesses (that's why I'm a member). Immersion vs sprinkle / adult vs infant is a hornets nest. Is one side damned and not the other? Nope, they're just missing out on another avenue of grace.
Salvation is pretty straight forward--
Mark 16:16 Revised Standard Version (RSV)
16 He who believes and is baptized will be saved; but he who does not believe will be condemned.
Some believe Baptism is a dedication to the Lord. That would be Law--something you must do. We believe Baptism is Gospel--something God does for us:
"Repent and be bapitized, every one of you, in the name of Jesus Christ for the forgiveness of your sins." (Acts 2:38) Words and grammar mean things. "be baptized"--why is that passive? Because God is the actor. Thru baptism God delivers faith and forgiveness--previously beyond our grasp. Before Baptism we were spiritually blind, deaf, and enemies of God. (Eph 2:1-2)
My fellowship likes to say, "Baptism is an unsinkable boat." Then why are some who are baptized still not saved?--Because they jump out of the boat.
We teach objective and subjective justification. When Christ said, "It is finished."-- all mankind of all time was justified before God (delared not guilty)--objective justification. God then delivers that justification to each individual by means of grace (word and sacraments). (subjective justification)
In the Church Service (Divine Service)--Who does the serving? God does and delights in it. Is there enough grace for salvation when God serves us through the Absolution? Yes. (Hopefully your pastor has an Absolution) Is there enough grace in the Scripture reading for salvation? Yes. Is there enough grace in the sermon for salvation? Yes. Is there enough grace in Baptism for salvation? Yes. Is there enough grace in the Lord's Supper for salvation? Yes.
Why does God provide so many avenues to grace when one is enough?
1. We are spiritually weak and sinful and constantly need to be reminded of grace.
2. God cannot contain His love. It simply gushes forth in many forms--all grace. "There is a fountain filled with blood, Drawn from Immanuel's veins. And sinners plunged beneath that flood Lose all their guilty stains." More like a tidal wave.
I know many will disagree with some of the points here. I have expressed the nuts and bolts of Baptism as clearly as I can. Probably not a great forum for Baptism as it could easily exceed 100 pages.