Well, not really, because we both are talking about sin after... having believed and been baptized. You are the one who is trying to introduce the idea of our first repentance and baptism. That first repentance and baptism was for sins that are past, according to Apostle Paul.
I don't... think... you're really up to speed on men's doctrines within today's Grace Movement. Some of those Churches are teaching no further repentance is needed after having believed on Jesus and been baptized. Some of them even treat it as if it were blasphemy to ask Him forgiveness for a sin committed after having become a Christian. That kind of doctrine is from devils, and goes directly against 1 John 1 and Luke 11.
As for your quote from Rom.6:2, you are not interpreting it correctly. You have to keep that verse with the flow of that Chapter. And in that Chapter Apostle Paul is telling us to reckon ourselves as dead to sin, while commanding us to not let sin reign in our mortal body, meaning to be watchful against sin. It does not mean we can no longer sin as believers. Paul is not saying that. Even the Greek for "reckon" in Rom.6:11 means exactly that, suppose or think of ourselves as being dead to sin, not as though we literally are, but to reckon that we are. This because in Galatians 5 Paul made it clear that IF... we walk by The Spirit, then we are dead to sin, meaning a condition based on our walk. If we don't, then he showed the result are those works of the flesh he listed.
Unwittingly? I just heard a witness from a brother the other day who at one time was so taken with a pretty girl at his work, that he was considering having an affair with her, was determined to do it, knowing that it was wrong, because it was at a time when his wife was cold towards him several months after she had a child. No, when we mess up, we do it good! We sin! And that's all there is to it. I could mention at least two TV preachers right now that had extra-marital affairs, which is the sin of adultery. Nah, those kind of things aren't done unwittingly. They are done because of lusts of the flesh, and that is what Apostle Paul commanded us to control and overcome.
In 1 Timothy 1, Apostle Paul even taught, as part of Christian Doctrine, that those who do those works of the flesh there he listed, shall not inherit the kingdom of God.
What is unfortunate, for you, is that you are wanting to side with men's doctrines who try to write their own Bible instead of keeping to what God's Word actually says about these things. And I pointed to 1 John 1, which is about John telling us to continue to repent to Jesus of future sin, which so far you refuse to address.