The sabbath was the day of worship that Paul knew to be the authentic, true sabbath of the Lord. It was the 4th commandment of God written down in scripture in multiple places and backed up by Jesus Christ and thousands of years of traditions.
Paul preached ON THE SABBATH to gentiles because that is and was the Christian day of worship.
What you're doing is looking at 1700 years of keeping Sunday and applying your understanding to scripture.
Hmm, did Ellen G White have Acts 20:7 removed from the Bible under inspiration?
I repeat, the Mosaic law was fulfilled and nailed to the cross. We are not to be worried about new moons, festivals and sabbaths. Jesus is our Sabbath, we rest in Him.
Show me one verse where Paul explains to the Gentile converts what the Sabbath day is for, why we need to keep it and how we should keep it.
You can’t!
The Christian Church never kept the Sabbath any more than we practice circumcision.
Christians follow the commandments of Christ, I asked if you knew what they were. No Sabbath is mentioned so maybe you never learned that.