Wrong premise.
Wrong summary.
Wrong conclusion.
In your note to Acts 15:2 you used "weather" instead of "whether."
Now let us review Acts 15 without a the SDA bias.
The Sabbath is mentioned 60 times in the NT but it is never mentioned in Acts through Revelation, in the writings specifically for gentile Christians.
Here are all the commandments specifically for gentile Christians. See e.g. Acts 15:1, 5, 1, 20-22, 15:24, 28:29-28, 21:24-26.
Acts 15:1
1 And certain men which came down from Judaea taught the brethren, and said, Except ye be circumcised after the manner of Moses, ye cannot be saved.
The only requirement in this vs. is circumcision, nothing about the Sabbath.
Acts 15:5
5 But there rose up certain of the sect of the Pharisees which believed, saying, That it was needful to circumcise them, and to command them to keep the law of Moses.
The requirements stated in this vs. are “circumcision” and “keep the law of Moses.” Which would be difficult unless they were also given the law of Moses. No record that gentile Christians were ever provided with copies of Old Testament law.
Acts 15:10
10 Now therefore why tempt ye God, to put a yoke upon the neck of the disciples, which neither our fathers nor we were able to bear?
Here Paul, a Jew, refers to the requirements of the Pharisees as "a yoke upon the neck of the disciples that the fathers were not able to bear."
Acts 15:20-21
20 But that we write unto them, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood.
21 For Moses of old time hath in every city them that preach him, being read in the synagogues every sabbath day.
The disciples listed only four requirements for gentile proselytes "abstain from pollutions of idols, fornication, things strangled and from blood."
No mention of Sabbath keeping. And note, vs. 21 does not mean the proselytes would be attending synagogues. Paul is certainly not so confused that he would call obeying the law of Moses a yoke that even the Jews could not bear and then a few sentences later say gentiles must attend synagogues where the Jews would be enforcing those very laws.
Acts 15:24
24 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:
Note Paul says they gave no such commandment i.e. "You must be circumcised, and keep the law."
Acts 15:28-29
28 For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things;
29 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.
These four only requirements are stated twice but there is no command for gentiles to keep the Sabbath? Paul, Barnabas, Judas Barsabas and Silas, said "no greater burden than these [four only] necessary things." No Sabbath command.
Acts 21:24-25
24 Them take, and purify thyself with them, and be at charges with them, that they may shave their heads: and all may know that those things, whereof they were informed concerning thee, are nothing; but that thou thyself also walkest orderly, and keepest the law.
25 As touching the Gentiles which believe, we have written and concluded that they observe no such thing, save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication.
vs.24 Paul preparing to take the Nazarite vow, vs. 24-25 "you [Paul] yourself walk orderly, and keep the law. Concerning the Gentiles which believe, we have written and concluded that they observe no such thing," i.e. "keep the law."
And they repeat the four only requirements for gentiles "save only that they keep themselves from things offered to idols, and from blood, and from strangled, and from fornication." Note, again only four requirements for gentiles and again there is no mention of Sabbath keeping for gentiles.
Because it is so lengthy the next post from, the Jewish Encyclopedia showing the historic Jewish attitude about gentiles, the law and the Sabbath.