Where does in it say in scriptures, they made a change in day, from sabbath to first/sun day then ???Gentiles Kept the Sabbath
So when the Jews went out of the synagogue, the Gentiles begged that these words might be preached to them the next Sabbath. Now when the congregation had broken up, many of the Jews and devout proselytes followed Paul and Barnabas, who, speaking to them, persuaded them to continue in the grace of God.
On the next Sabbath almost the whole city came together to hear the word of God. But when the Jews saw the multitudes, they were filled with envy; and contradicting and blaspheming, they opposed the things spoken by Paul.
At no point dies this prove anything you say in fact it’s actually boring to hear SDA gymnastics.
This is a description not a prescription
Of course, your proof need to carry with the Authority of GOD's Own Words.
Yours in Christ, Michael