There are many verses that describe the Mosaic Law as being instructions for how to walk in God's ways, such as Deuteronomy 10:12-12, Isaiah 2:2-3, Joshua 22:5, Psalm 103:7, and many others, so the Law was primarily given as instructions for how to act in accordance with God's nature and to express His character traits, such as holiness, righteousness, goodness, justice, mercy, faithfulness, love, joy, peace, patience, kindness, gentleness, and self-control. Jesus expressed these character traits through his actions and what that looked like is complete obedience to the Mosaic Law, so that is what it looks like when he is living in us. Pointing out our sin has significance only insofar as it leads us to repent and back to walking in God's ways through faith.
Passing from death to life is about dying to living in sin and rising again to new newness of life in obedience to God's Law.
The Spirit is not in disagreement with the Father about which laws we should follow and will not lead us to disobey what He has commanded, but rather in Ezekiel 36:26-27, the Spirit has the role of leading us to obey God's Law. In Romans 8:4-7, those who walk in the Spirit are contrasted with those who have carnal minds who refuse to submit to God's Law. In Galatians 5:19-22, everything listed as caral works that are against the Spirit are also against the Mosaic Law, while all of the fruits of the Spirit are in accordance with it, so the Spirit teaches us to obey the Mosaic Law.
In Psalm 119:45, the Mosaic Law is described as a law of liberty, so that is what it has always been. The written code is not useful for the carnal mind because the carnal mind refuses to submit to it. In John 14:23-24, Jesus said that if we love him, then we will obey his teachings, if we don't love him, then we will not obey his teachings, and that his teachings were not his own, but that of the Father, so if we love Jesus, then we will obey what the Father has taught. He notably did not say that once we are mature enough, his teachings are no longer necessary.