I don't believe 1 Peter 3:21 is saying what you're suggesting it does, lets look at it, here is 1 Peter 3:18-22
18 For Christ also suffered once for sins, the just for the unjust, that He might bring us[e] to God, being put to death in the flesh but made alive by the Spirit, 19 by whom also He went and preached to the spirits in prison, 20 who formerly were disobedient, when once the Divine long-suffering waited[f] in the days of Noah, while the ark was being prepared, in which a few, that is, eight souls, were saved through water. 21 There is also an
anti-type which now saves us—baptism (not the removal of the filth of the flesh, but the answer of a good conscience toward God), through the resurrection of Jesus Christ, 22 who has gone into heaven and is at the right hand of God, angels and authorities and powers having been made subject to Him.
He specifically says "there is also an ANTI-TYPE which saves us". Here is the definition of anti-type-
an·ti·type
ˈan(t)iˌtīp/Submit
noun
noun: anti-type
1.
a person or thing that represents the opposite of someone or something else.
2.
something that is represented by a symbol.
I would think that the 2nd definition would fit the context of this passage best. The fact that we do die to ourselves, the old man, the flesh, the slave of sin, whatever you call it dies at rebirth, and in and by the Spirit you are raised all new, a new man with new desires, new eyes, and new life. This was exactly what I experienced when I was reborn (born of Spirit), and this happened without a man physically dunking me under water. I was baptized in water way before this and wasn't saved, then I was saved without being physically dunked under water. I do not agree with what you're saying here that baptism saves, nothing we "do" saves us aside from believing (and I would say realizing that we can't do life without God and submitting, but I also think that "believing" is a much bigger word than we normally think of it as), baptism no more saves us than circumcision and you know what Paul says about that. I just disagree that the verse you're citing here means what you're saying it means. I just KNOW that I was saved and made new without having been dunked, even though I was baptized again after my true rebirth to publicly proclaim my salvation, but not to earn it. I'm not trying to just argue with you, or just "be right" and "teach", because I like and appreciate your civil tone, well thought and laid out view, and your very apparent love and passion for our Lord Jesus Christ, I just wanted to share why I can't agree with your point here, and share why & how I was saved without any kind of fleshly work. I hope you have a great day sister.