Whoever call upon the Lord will be saved, but how do we call on the Lord? Just calling Him Lord does not save (Matt 7:21). So how do we call on the name of the Lord and it result in salvation? By doing what He says (Matt 7:21).
You are correct that Rom 6:4 does not mention water.
But according to
Eph 4:4-6 there is only one baptism of significance in the NT.
That of the spirit baptizing man into Christ, Not the symbolic baptism with water
I say with because the bible never speaks of baptism into water
Hebrews 6:2 (KJV 1900) — 2 Of the doctrine of
baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment.
The context of Eph 4 speaks of the body and the spirit as we see here
1 Corinthians 12:13 (KJV 1900) — 13 For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
this baptism is that of the Spirit not water
And according to
1 Pet 3:21 and
Acts 8:36 that baptism is baptism into water.
Acts 8;36 speaks of a baptism with water not a baptism into Christ
and these are not baptisms into or with water
Matt 3:11 I indeed
baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall
baptize you with the Holy Ghost, and with fire:
Mark 1:8 I indeed have baptized you with water: but he shall
baptize you with the Holy Ghost.
Luke 3:16 John answered, saying unto them all, I indeed
baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose: he shall
baptize you with the Holy Ghost and with fire:
Acts 1:5 (KJV 1900) — 5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
Acts 11:16 (KJV 1900) — 16 Then remembered I the word of the Lord, how that he said, John indeed baptized with water; but ye shall be baptized with the Holy Ghost.
And according to
Matt 28:19 that baptism is an act that man does.
and according to
Matt 3:11 I indeed
baptize you with water unto repentance: but he that cometh after me is mightier than I, whose shoes I am not worthy to bear: he shall
baptize you with the Holy Ghost, and with fire:
Mark 1:8 I indeed have baptized you with water: but he shall
baptize you with the Holy Ghost.
Luke 3:16 John answered, saying unto them all, I indeed
baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose: he shall
baptize you with the Holy Ghost and with fire:
Acts 1:5 (KJV 1900) — 5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
Acts 11:16 (KJV 1900) — 16 Then remembered I the word of the Lord, how that he said, John indeed baptized with water; but ye shall be baptized with the Holy Ghost.
The spirit not water is the baptizing element
And according to
Col 2:11-14 and
Rom 6:1-7 that baptism is the point at which our sins are cut from us, and we are united to Christ in His resurrection.
So the baptism in which we are saved does require water.
again there is no water in Romans 6 or Col 2:11-14 for that matter