You also didn’t explain the context of Galatians. Paul is not writing general commentary on the Law and Christ. He has an angle for writing. The Galatians are worried that they must get circumcised to be true people of God. This would be a valid concern, per Genesis 17:9-14 and Exodus 4:24-26, but Paul wants to discourage this because he feels it negates the work of Christ (Gal 5:2-6). This is, shall we say odd, in light of the account of Paul in Acts 16:3. Nevertheless, Paul is arguing against circumcision (or following the Law) being a requirement of being a child of God – not that the Law no longer matters in ANY context and thus, all the other 613 laws should not be followed.