Jesus did not make any statement that made the sabbath appear as if it would disappear.
The sabbath was so well kept in Jesus's day. it was over done, the Jewish people had made it a burden.. over kept.
Jesus didn't need to remind them..
He needed to help them see the difference between the way God intended them to keep it and the way they were placing extreme laws on it.
Mar 2:27-28
27 And he said unto them, The sabbath was made for man, and not man for the sabbath: 28 Therefore the Son of man is Lord also of the sabbath.
If the Sabbath was about to pass away. Why did Jesus say He is Lord of the Sabbath?
There is nothing saying the 10 commanents stopped at the cross. Or the sabbath stopped at the cross.
The question is was it a shadow law or a moral law?
The school master was finished and the laws that pointed to Jesus were nailed to the cross..
The sabbath is one of the 10. And it was established before sin.
The sabbath is pointing us to creation and the creator. The cerimonial laws pointed to Jesus the lamb that gave His life.
I agree that Jesus never spoke as though the Sabbath were a burden to be discarded.
In fact, Mark 2:27-28 shows Him correcting abuses of the Sabbath, not attacking the Sabbath itself.
He said, "The sabbath was made for man," which certainly emphasizes its benefit rather than its abolition.
However, I think you're making a subtle shift in the argument.
Originally, the claim was that the Sabbath remains binding because it is part of the moral law.
Now the support being offered is that Jesus never explicitly said it would disappear.
Those are not quite the same argument.
There are many things the New Testament does not explicitly say will disappear, yet the question is how the apostles later treated them after Christ's death and resurrection.
You ask, "If the Sabbath was about to pass away, why did Jesus say He is Lord of the Sabbath?"
My answer would be that being Lord of something does not by itself tell us whether its administration remains unchanged.
Christ is Lord of the Temple, yet the Temple system reached its fulfillment in Him.
Christ is Lord of the priesthood, yet Hebrews teaches a change in priesthood.
So the title itself does not settle the question one way or the other.
Where I think your argument is strongest is when you point back to creation.
If the Sabbath was truly established for all mankind at creation and not merely for Israel under Sinai, then that is a significant consideration.
But even then, I return to the same question: how do the apostles apply that in the New Covenant?
When they teach the churches, I do not find them saying, "Remember the Sabbath day."
Instead, I find them emphasizing faith in Christ, life in the Spirit, love of neighbor, and liberty regarding the observance of days.
So I agree that the Sabbath is not easily dismissed as merely another ceremonial ordinance.
But neither do I see the apostles arguing for it the way they argue for commands against idolatry, adultery, murder, theft, or covetousness.
That is why I remain unconvinced by both extremes: I do not think the Sabbath can simply be waved away, yet I also do not see an explicit New Covenant command requiring believers to keep it as Israel did under the Mosaic covenant.
To me, the central issue remains this: not whether the Sabbath existed before Sinai, but how the inspired apostles instructed the church concerning it after the cross and resurrection.
That is where I believe the discussion must ultimately be settled.