Nowhere are we told to keep the Sabbath. Here's what we are to keep.
“Forasmuch as we have heard, that certain which went out from us have troubled you with words, subverting your souls, saying, Ye must be circumcised, and keep the law: to whom we gave no such commandment:” Acts 15:24 (KJV 1900)
“For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things; That ye abstain from meats offered to idols, and from blood, and from things strangled, and from fornication: from which if ye keep yourselves, ye shall do well. Fare ye well.” Acts 15:28–29 (KJV 1900)
(This is not OT Law. If so, it would require returning to the entire Old Covenant. It is NT law that pre-dates the OT. Genesis 9:4 shows abstinence from blood commanded by God to Noah.
Joshua 24:2 shows the idol worship Abraham's ancestors.
So the point being that since similarities exist in the Old Covenant, they do not place us back under the OT.
“As they went through the towns, they passed on the decrees that had been decided on by the apostles and elders in Jerusalem for the Gentile believers to obey.” (Acts 16:4)).