I also believe penal substitution may not be correct although I haven't studied it a lot.
Could you please tell me what you DO believe?
"If you eat this fruit you shall surely die"
NOT
" If you eat this fruit I will kill you".
The Penal Substitution model is a development of Anselm's Satisfaction model developed in the 12th century. Thomas Aquinus added the idea of a "satisfactory punishment" being universally applied in order to "pay the price" for sin. Later it was the Reformers who introduced judicial language to these ideas and the Penal Substitution model was born.
All the substitution models are unbiblical and erroneous.
I simply believe what the Bible plainly teaches. Jesus died for the cause of purging our conscience of dead works in order that we may serve the living God.
Heb 9:14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your conscience from dead works to serve the living God?
Heb 9:15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
Heb 9:16 For where a testament is, there must also of necessity be the death of the testator.
Heb 9:17 For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth.
When a human being rebels against God it defiles the conscience and even a return to obedience cannot remove the consciousness of sins. Thus under the Old Covenant people would measure themselves outwardly according to rite, ritual, rule and regulation. An outward focus is dead because true life is only wrought through the Spirit.
The blood of bulls and goats could not remove a consciousness of sin in an individual because it was purely an outward mechanic, ie. a ritualistic process. The real issue being the heart, and not some legal adjustment.
Heb 10:1 For the law having a shadow of good things to come, and not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect.
Heb 10:2 For then would they not have ceased to be offered? because that the worshippers once purged should have had no more conscience of sins.
Heb 10:3 But in those sacrifices there is a remembrance again made of sins every year.
Heb 10:4 For it is not possible that the blood of bulls and of goats should take away sins.
With Jesus Christ the dynamic involves a total renovation of the inward man as we enter into covenant with God via the blood. Hence we read...
Heb 10:19 Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus,
Heb 10:20 By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;
Heb 10:21 And having an high priest over the house of God;
Heb 10:22 Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water.
The result of this produces this...
Heb 10:14 For by one offering he hath perfected for ever them that are sanctified.
Heb 10:15 Whereof the Holy Ghost also is a witness to us: for after that he had said before,
Heb 10:16 This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them;
Instead of outward comparison to rules and regulations like with the Old Covenant, we are inwardly refreshed with the love of God shed abroad in our hearts. Thus we walk by a faith that works by love which fulfills the righteousness of the law, hence we are no longer under the law for the law is obsolete for those whom have been made righteous in Christ.
The core of Jesus message was...
Joh 17:23 I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me.
Thus we find union with God through the Spirit of life IN Jesus Christ. That is the Gospel. Not some magical legal transfer as is taught under substitution theology.
I'll send you a free book which I wrote on the subject if you like, it examines this subject in a historical context and demonstrates how the modern theological teaches slowly developed over time. Modern professing Christianity is far removed from what early Christianity taught.