I am outright proclaiming that Christ is our substitute only in terms of representation
Which is to say that Christ is not our substitute.
A substitute is a replacement. A representative is an emissary. Christ replaced us on the Cross. That Cross and it's curse, meaning the guilt of transgression and the just penalty thereof, was ours. But we have been spared that Cross in Him.
We have been saved from wrath.
That is what it means to say He was made a curse for us.
We do not have to bear the Cross that Christ bore for us. The crosses we bear are the suffering for righteousness' sake, which you so egregiously conflate with what it means to suffer for sins. Yes, Christ suffered long His entire life, but that was a patience with sheep with no shepherd, and a suffering for the sake of righteousness. His suffering for sin was on the Cross, where He bore our own sins in His own body on the Tree. He was not bearing our sins at His birth, nor as a refugee in Egypt, neither when chided by His mother in Cana, nor when slandered by the Pharisees, or tempted by Satan.
He didn't suffer often for sins; He suffered once for sins. 1 Peter 3:18 The Rock was stricken once. It followed them in the Wilderness, and they were 40 years in the Wilderness because of unbelief, but it was stricken justly one time. To strike it a second time is to be left to die in the Wilderness. The veil was torn once, and it wasn't a gradual thing.
So where is it that we are told that He bore our sins? Where was it that He was stricken? Where was His body broken? (His flesh is what is represented by the veil Hebrews 10:20 ) I will repeat the question for those who think that God cannot in truth take another's sins upon Himself.
Where did He bear OUR sins? Not His. He had none. But our OWN sins?
Ah--yes. It was on the tree.
But
@JonC asserts that Christ must have suffered often for sins. Jon would have been playing whack-a-mole on that Rock. He'd have had that veil cut to ribbons.
exactly in the manner that Adam is the representative of natural man (which is the biblical understanding of "in Adam" as we are by nature Adam's progeny).
The biblical understanding is that we were really there, so death passed upon all. That's where the human race was corrupted. We were all in Adam. Not just potentially, or figuratively, or legally, but really there.
And we were really in Christ.