No one has denied that Jesus' death was substitutionary, so that's not the gridlock.
To help dialogue, let's just look at each other's position thus far.
I hold that Paul spoke of sins more often in the singular. So I contend that Paul's focus is not on divine justice against sins we have committed but on sin as a power exercising dominion over mankind. I've argued that Paul looks at man as needing a savior who could break the power of sin under which men are enslaved, one who could set us free from the law of sin and death.
As evidence of this type of reasoning in the writings of Paul I have offered Eph 1:17, Col 1:14, 1 Corinthians 15:3, Gal 1:4, Romans 3:9, Corinthians 15:15, Galatians 3:22, Romans 5:21, Romans 6:12, Romans 6:6-7 and Romans 8:2...among others.
What I am looking for are passages affirming that God was wrathful towards Jesus, punishing him with the punishment we would have received at Judgment, etc. If the only part of your theory that is biblical is that Jesus' death was on a substitutionary basis then we agree insofar as Scripture goes and our disagreement is simply on the parts your theory adds.