Why Jesus’ death is needed IMHO:
In the beginning Adam and Eve basically followed Satan, leaving God. This makes Satan Adam and Eve’s God. Dead to rights Satan now had the authority to do as he pleases with humans, but Satan Himself is under the Lord, and the Lord has the right to impose anything on Satan He wants, which because He is the Lord, will be in line with righteousness. The Lord holds back on judging Satan fully, because as Satan goes, so does his followers, namely Adam and Eve and all humanity, and imposes a much lesser sentence.
This mercy extended to Satan allowed God to mediate for us, buying us much freedom that would not be if Satan had full control over us. God allowed strict rules that incurred various curses when broken to be placed on humanity, but also allowed us freedom to have certain freedoms, these freedoms would be a path to Love and children - which would allow Jesus.
Jesus came into this world lived and was condemned to die, though He committed no sin as far as the Father was concerned, very possibly Satan thought otherwise as Jesus violated the written code, healing on the Sabbath. That death was payment for every sin ever committed, as if you commit one sin you are as guilty as someone committing 100 sins, the sentence is the exact same one sin = sin, one hundred sins = sin, penalty = death. Jesus had to pay that penalty which He did, but since He was sinless death could not hold Him and He was resurrected.
Now that penalty is pre-paid, so when some becomes one with Jesus, that prepayment has been made in our behalf - we become one with Jesus through the marriage between Jesus and the church, any sin is already paid in full, and since one or many sins are the same, no other penalty can be imposed.
This is what is know as grace, when one is under grace they are not under the law, the penalty has been paid, but just as Jesus followed the Holy Spirit, the believer must follow the Holy Spirit, which will lead the believer to live in Love, of which there are no laws.
The restrictions of the Law have been lifted at this point, which God never wanted for us.
What about disobedient believers? God will try to correct them, many times, but if they still resist they will (God will allow them to) shipwreck their faith. They will be of no use to the advancement of God’s Kingdom, but will be saved when their life is done.