None of these verses talk about obeying Torah.
The Torah is how we know what sin is, so how can Jesus calling sinners to repentance not be speaking about obeying the Torah ?
“Gospel of the Grace of God” is not being under the Mosaic law, we go far beyond it as we walk in the Spirit
In Psalm 119:29-30, he wanted to put false ways far from him, for God to be graciously to hi by teaching him to obey the Torah, and he chose the way of faith by setting it before him, so this is what it means to be under grace, this is why those who are under grace and not permitted to transgress the Torah (Romans 6:15), and this has always been the one and only way of salvation by grace through faith. The Gospel of Grace is not an alternative to how God is gracious to us but is in accordance with it.
God has not commanded anything that is not in accordance with walking in the Spirit, but rather God's character traits are the fruits of the Spirit and the purpose of the Torah is to teach us how to embody God's character traits, which is why the Spirit has the role of leading us to obey it (Ezekiel 36:26-27). In Romans 8:4-7, Paul contrasted those who walk in the Spirit with those who have minds set on the flesh who are enemies of God who refuse to submit to the Law of God, so the Spirit does not lead us to do anything that is not in accordance with it. The Son is the radiance of God's glory and the exact likeness of His character (Hebrews 1:3), which he embodied through his works by setting a sinless example for us to follow of how to walk in the Spirit/how to walk in obedience to the Torah.
.Paul convinced them about Jesus from the law of Moses and from the prophets. He was not convincing them to obey the law of Moses, he used Moses law to explain Christ.
The Torah is God's Word and Jesus is God's Word made flesh so everything that it true about Jesus is also true about the Torah insofar as he is the embodiment of it.
Romans 8:3
For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh:
The Torah does not have the power to cause us to embody it, which is why the one who is the embodiment of it has the role of helping us to do that. We have been set free from sin so that we can be free to obey the righteous requirement of the Law of God (Romans 8:4).
Romans 6:14
For sin shall not have dominion over you, for ye are not under the law, but under grace.
Paul spoke about the Torah as being something that is the good that he wanted to do in contrast with the describing the law of sin as being something that was causing us not to do the good that we want to do. In Romans 6:14, it describes the law that we are not under as being a law where sin had dominion over us, which clearly is not describing something that is the good that Paul wanted to do, but rather that is the role of the law of sin. In Romans 6:15, being under grace does not mean that we are permitted to sin, and in Romans 7:7, the Law of God is not sinful [unlike the law of sin] but how we know what sin is, so we are still under the Law of God but are not under the law of sin. Moreover, everything else in Romans 6 speaks in favor of obedience to God and against sin.