My point is the man of sin is our old man that has been crucified with Christ, not a future antichrist.
The verses about the man of sin say nothing about him being crucified with Christ. It doesn't match your interpretation.
2Th 2:3 Let no man deceive you by any means:
for that day shall not come, except there come a falling away first, and that man of sin be revealed,
the son of perdition;
2Th 2:4 Who opposeth and exalteth
himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God.
That's not at all related to our "old man" being replaced by a new person in Christ. It's clearly a ruler who will claim to be God and is directly related to the time period which happens before the second coming as Paul addresses above.
2Th 2:5 Remember ye not, that, when I was yet with you, I told you these things?
2Th 2:6 And now ye know what withholdeth that he might be revealed in his time.
2Th 2:7 For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way.
2Th 2:8 And then shall
that Wicked be revealed, whom
the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming:
He isn't even destroyed until the second coming!