I'm sorry, but I see no way to read Galatians, Romans 14, Acts 15, and other verses and come away with saying that Paul did not teach that circumcision, sabbath observance, and the kosher laws were at best optional. The text is quite explicit about that, especially circumcision.
Christ spent his ministry teaching his followers to obey the Torah by word and by example and I don't see how it makes sense to interpret those as speaking against following Christ. It is important to recognize that Paul can speak against obeying what God has commanded for an incorrect reason without speaking against obeying what God has commanded. If Paul had been speaking against circumcision for any reason, then according to Galatians 5:2, Paul caused Christ to be of no value to Timothy when he had him circumcised and Christ is of no value to roughly 80% of the men in the US. In Acts 15:1, men from Judea were wanting to require Gentiles to become circumcised in order to become saved, however, that was never the reason for which God commanded circumcision, so the Jerusalem Council upheld the Torah by correctly ruling against requiring circumcision for an incorrect reason. In Exodus 12:48, a Gentile who wanted to eat of the Passover lamb was required to become circumcision, so the Jerusalem Council should not be interpreted as ruling against Gentiles correctly acting in accordance with what God has commanded as if they had the authority to countermand God.
It is also important to recognize that Paul spoke about multiple categories of law other than the Law of God, so it is always important discern which law he is referring to. For example, in Romans 7:25-8:2, Paul contrasted the Law of God with the law of sin and contrasted the Law of the Spirit of Life with the law of sin and death. In Romans 3:27, Paul contrasted a law of works with a law of faith, in Galatians 3:10-12, he contrasted the Book of the Law with "works of the law" and in Romans 3:31, he said that our faith upholds the Law of God in contrast with saying that "works of the law" are not of faith, so that phrase does not refer to the Law of God.
Moreover, it is also important to be careful not to mistake what Paul said in regard to following the teachings or opinions of men as being in regard to following the commandments of God. In Romans 14:1, the topic of the chapter is in regard to how to handle disputable matters of opinion in which God has given no command, not in regard to whether followers of God should follow God. For example, in Romans 14:2-3, they were judging and resenting each other based on whether or not someone chose to eat only vegetables even though God has given no command to do that.
In Romans 14:4-6, Paul spoke about those who ate or refrain from eating, so he was speaking about those who esteemed certain days for fasting as a disputable matter of opinion. In the 1st century it had become a common practice to fast twice a week and people were judging and resenting each other based on whether or not someone chose to do that even though God gave no command to do that (Luke 18:12). The Sabbath is not even mentioned in Romans 14 precisely because it had nothing to do with the topic that Paul was discussing. Paul was not suggest that we are free to break the Sabbath, or disobey God's commands against committing murder, idolatry, adultery, theft, kidnapping, rape, favoritism, or any of God's other commands just as long as we are convinced in our own minds that it is ok to rebel against God, but rather that was only said in regard to things that are disputable matters of opinion in which God has given no command.