That it doesn't discuss the atonement right at that time doesn't warrant any conclusion about the whether God can justly forgive on the basis of our repentance alone - only that it is the requirement on the part of us.
I strongly disagree.
There are several points to Ezekiel. Do not punish the sons for the sins of the father. God's justice is different from what Israel had been doing. Etc.
But the main point is repentance and forgiveness.
The only requirement in Scripture (in the entirety of Scripture) for forgiveness is repentance.
Scripture describes this requirement several ways - "repent and believe", "make a new heart", "turn to God", "set your mind on the Spirit", "die to sin", "die to the flesh", etc.
This is fulfilled in Christ. We cannot make ourselves anew. But through faith God will.
Do you know of a passage that states God forgives sins apart from repentance?
Repentance and belief (turning from the flesh, turning to Christ) is the only way. Christ is the only Way.
You are confusing punishment as righteousness (justice).
God will punish the wicked when He exercises judgment on the world (the Day of Judgment).
But punishment itself is not righteousness (justice). Punishment is a means to an end (righteousness, or justice).
The kingdom of God is a righteous (just) kingdom. The new heavens and new earth will have no place for unrighteousness (the unrighteous will not enter the kingdom of God).
God "casts out" (judgement, punishing the wicked, the second death) the unrighteous (the wicked). Why? Because they have no place in the new creation (it is holy, righteous).
God would be unjust if He punished those who repented when He judges because we will not be wicked. We will have been made into the image of Christ.
God achieves in us what punishment could not. Punishment is casting out evil (read the purpose of the Law as relates to Israel in Deuteronomy).
God can forgive sins. Your ideas that God must punish sins in order to "forgive" those sins negates forgiveness itself.
Why would God punish the sins of those who have died to sin, been made a new creation, been conformed into Christ's image, been made righteous?
For justice He would not need to. He would have accomplished justice in a way different from the law but not contrary to the law.
You are arguing from a standpoint of secular philosophy (not Scripture). The requirements you place on God are not from the Bible but worldly "wisdom".