Far from being incorrect, Jesus began his ministry with the Gospel message to repent for the Kingdom of God is at hand (Matthew 4:17-23), and the Mosaic Law was how his audience knew what sin is, so repenting from our disobedience to it is an integral part of the Gospel message, which Jesus prophesied would be proclaimed to all nations (Matthew 24:12-14). In Titus 2:11-14, our salvation is described as being trained by grace to do what is godly, righteous, and good, and to renonce doing what is ungodly, which is what the Mosaic Law was given to instruct how to do. Furthermore, Titus 2:14 does not say that Jesus gave himself to free us from God's law, but in order to redeem us from all lawlessness and to purify for himself a people of his own possession who are zealous for doing good works, so saying that we are freed from God's law undermines both Christ's ministry and what he accomplished on the cross. In Psalms 119:29, David wanted God to be gracious to him by teaching him to obey His law, so that is what being under grace looks like.
In Hebrew 4:6, they did not enter God's rest because of their disobedience, and in 4:11, we should strive to enter that rest so that no one may fall away by the same sort of disobedience, so you using entering into God's rest to justify the same sort of disobedience is exactly what the opposite of what was being said. Christ set a sinless example for us to follow of how to walk in obedience to the Mosaic Law, he did not hypocritically preach something other than what he practiced, and as Christians we are obligated to follow what Christ taught by word and by example. In Matthew 11:28-30, Jesus was inviting people to come to him for rest and to learn from him, not inviting people to refuse to follow what he taught. By saying that we would find rest for our souls, he was referencing Jeremiah 6:16-19, where the Mosaic Law is described as the good way were we will find rest for our souls. This rest for our souls comes from having faith in God to guide us in how to rightly live through His law, not from taking a break from following God's guidance.