God wrote the New Covenant Hebrews 8:10, Jeremiah 31:33 and God’s laws are now written in the heart, which of course includes the holy day of the Lord thy God and 4th commandment.
Jesus kept the laws of His Father and never came to destroy God’s laws John 14:15, Mathew 5:17-20 Jesus came to magnify the law Isaiah 42:21
Which is why the Sabbath is still a commandment in the New Testament Matthew 12:2, Luke 23:56 and why Jesus kept the Sabbath reading scriptures in the Temple as was His custom Luke 4:16 and Jesus telling us the Sabbath was made for man Mark 2:27
I noticed you did not provide scripture in your post so how does your opinion compare with the Word of God on these really easy to read scripture below:
Exodus 20: 8 “Remember the Sabbath day, to keep it holy. 9 Six days you shall labor and do all your work, 10
but the seventh day is the Sabbath of the Lord your God.
In it you shall do no work: you, nor your son, nor your daughter, nor your male servant, nor your female servant, nor your cattle, nor your stranger who
is within your gates. 11 For
in six days the Lord made the heavens and the earth, the sea, and all that
is in them, and rested
the seventh day.Therefore the Lord blessed the Sabbath day and hallowed it.
Isaiah 58:13 “If you turn away your foot from the Sabbath,
From doing your pleasure on
My holy day, And call
the Sabbath a delight
The holy day of the Lord honorable, And shall honor Him, not doing your own ways,
Nor finding your own pleasure, Nor speaking
your own words, (how can you possibly argue the Lord's day is the first day when this makes it so clear which is the Lords day)
Mark 2:28 28 Therefore the Son of Man is also
Lord of the Sabbath.”
There is no scripture telling us Sunday is the Lords day or God’s new holy day. Which is why the Sabbath will continue for eternity to be God’s chosen day and not the first day. Isaiah 66:23
God bless!