The FACT that the apostle John mentions the LORD'S DAY in Revelation should suffice. That is not tradition but divine revelation. The Lord's Table and the Lord's Supper belong to the Lord's Day. And it is definitely not the Sabbath, since had it been the Sabbath, it would not have been called "the Lord's Day".
As to the claim that the Lord arose on the Sabbath, that is patently false on the face of it. The Sabbath means REST, and the Lord would not rise on the day which He designated for His own rest. The end of the Sabbath = the beginning of the first day of the week. So the first day of the week began at sunset on Saturday and ended at sunset on Sunday. However the Lord probably rose from the dead after midnight. Christ is called the First Fruits of them that slept, and that fulfilled the Feast of First Fruits on the morrow AFTER the Sabbath.
Speak unto the children of Israel, and say unto them, When ye be come into the land which I give unto you, and shall reap the harvest thereof, then ye shall bring a sheaf of the firstfruits of your harvest unto the priest: And he shall wave the sheaf before the LORD, to be accepted for you: on the morrow after the sabbath the priest shall wave it. (Lev 23:10,11)
Firstfruits is the presenting to the Father, that is why Mary could not touch Him:
John 20:17-18,Jesus said to her, “Do not cling to me, for I have not yet ascended to the Father; but go to my brothers and say to them, ‘I am ascending to my Father and your Father, to my God and your God.’” Mary Magdalene went and announced to the disciples, “I have seen the Lord”-and that he had said these things to her.
In Revelations 1:10 no where does it say it is the 1st day, you are just making up what day John was having a vision on...
Rev1:10, "I was in the Spirit on the Lord's (G2960) day, (G2250) and heard behind me a great voice, as of a trumpet."
Lord's G2960 κυριακός kuriakos (kï-riy-a-kos') adj.
belonging to the Lord (Jehovah or Jesus).
[from G2962] KJV: Lord's Root(s): G2962 Lord κύριος kurios (kï '-riy-os) n.
DAY referring to the Sabbath (Luke 4:16; 13:14; 16; 14:15; John 5:9; Acts:13:14)
Also
He was already risen by then..
every gospel says it:
Matthew 28:1-6, “But late in the sabbath, as it was dawning into day one of the week, Miryam from Maḡdala and the other Miryam came to see the tomb. And see, there was a great earthquake, for a messenger of יהוה came down out of heaven, and came and rolled back the stone from the door, and sat on it. And his appearance was like lightning, and his garments as white as snow. And the guards trembled for fear of him, and became like dead men. And the messenger responding, said to the women, “Do not be afraid, for I know that you seek יהושע who was impaled. He is not here, for He was raised, as He said. Come, see the place where the Master lay.”
“it was dawning into day one of the week”...“He is not here, for He was raised”
Mark 16:1-6, “And when the Sabbath was past, Miryam from Maḡdala, and Miryam the mother of Ya‛aqoḇ, and Shelomah bought spices, to go and anoint Him. And very early on day one of the week, they came to the tomb when the sun had risen. And they said among themselves, “Who shall roll away the stone from the entrance of the tomb for us?” And looking up, they saw that the stone had been rolled away, for it was extremely large. And having entered into the tomb, they saw a young man sitting on the right, wearing a white robe, and they were greatly astonished. And he said to them, “Do not be much astonished. You seek יהושע of Natsareth, who was impaled. He was raised – He is not here! See the place where they laid Him.”
“very early on day one of the week”...“He was raised – He is not here”
Luke 24:1-3, “But on day one of the week, at early dawn, they came to the tomb, bringing the spices which they had prepared, and they found the stone rolled away from the tomb. And having entered, they did not find the body of the Master יהושע.”
“on day one of the week, at early dawn”...“they did not find the body of the Master יהושע”
John 20:1, “And on the first day of the week Miryam from Maḡdala came early to the tomb, while it was still dark, and saw that the stone had been removed from the tomb.”
“on the first day of the week”...“the stone had been removed from the tomb”