We should only "scrap" what the Lord Himself has "scrapped." On the cross Jesus himself put away any need, under the Law, for further attempts at self-justification. Works of the Law could never, after all, self-justify. They could only provide obedience, resulting in temporal blessings--they could not bring eternal life.
So any efforts at self-justification through Sabbath-keeping, were done away with, or "scrapped," at the cross. To try to bring that law back does an affront to Christ, as the NT Scriptures say. This would insult the "Spirit of Grace."
Heb 10.29 How much more severely do you think someone deserves to be punished who has trampled the Son of God underfoot, who has treated as an unholy thing the blood of the covenant that sanctified them, and who has insulted the Spirit of grace?
Paul makes a very big issue out of this by denouncing those who continued to pursue justification under the Law.
Gal 3.10 For all who rely on the works of the law are under a curse, as it is written: “Cursed is everyone who does not continue to do everything written in the Book of the Law.” 11 Clearly no one who relies on the law is justified before God, because “the righteous will live by faith.”
Obviously, nobody can perfectly "continue under the Law." Having a sin nature, we will always sin, as long as we live in these fallen bodies. So we can experience blessings for obedience in this life, by practicing righteousness. But without eternal atonement, we can never receive eternal life.
For Paul, living by faith was a matter of entering into the righteousness of Christ apart from any rituals to justify access to it. It was a free gift, not requiring any act under the Law in a preliminary way. To engage in Sabbath observance was rejected by Paul.
Col 2.16 Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day.
To pursue circumcision itself, the very act of male entry into the Covenant of Law, was showing disrespect for Jesus' death, if the act of circumcision was taught as anything but a tradition.
Gal 6.15 Neither circumcision nor uncircumcision means anything; what counts is the new creation.
Even the OT priesthood was contaminated, and could only bring temporal blessings--not eternal justification. It was shown under the Law that even the priests were unclean and had to be atoned for.
In the same way, all works of the Law had to be brought to an end at the crucifixion of Christ, where all the works of men were shown to be unclean, and incapable of eternal justification. Righteousness continues to be needed and is still required by God. But the Law proved incapable of being the vehicle through which eternal justification could come, and was done away with when Israel failed under that system.
Eternal Life therefore comes only by embracing the free righteousness that comes to us when we repent of living our own life, apart from God. All rituals of the Law, including Sabbath Law, have to go by the wayside, or "scrapped." Israel failed under that system, and we all would.