The shadows are what the Bible says they are....
Heb 10:1
For the law, having a shadow of the good things to come,
and not the very image of the things, can never with
these same sacrifices, which they offer continually year by year, make those who approach perfect. 2 For then would they not have ceased to be offered? For the worshipers, once [
a]purified, would have had no more consciousness of sins. 3 But
in those sacrifices there is a reminder of sins every year. 4 For
it is not possibl
e that the blood of bulls and goats could take away sins.
5
Therefore, when He came into the world, He said:
“Sacrifice and offering You did not desire,
But a body You have prepared for Me.
6 In burnt offerings and
sacrifices for sin
You had no pleasure.
7 Then I said, ‘Behold, I have come—
In the volume of the book it is written of Me—
To do Your will, O God.’ ”
8 Previously saying, “Sacrifice and offering, burnt offerings, and
offerings for sin You did not desire, nor had pleasure
in them” (which are offered according to the law), 9 then He said, “Behold, I have come to do Your will, [
b]O God.” He takes away the first that He may establish the second. 10 By that will we have been [
c]sanctified through the offering of the body of Jesus Christ once
for all.
The weekly Sabbath came before sin, before the fall and was never a shadow of God, but points to Him as our Creator Exo20:11 the only God we are to worship Rev14:7
If you wish to force Paul to teach against Christ, when Paul said everything had to be according to Him and teach that spending sanctified time honoring our LORD, God's blessing, the day that our Savior Jesus Christ is LORD of, is against man, that will have to be between those and God. Its certainly not what Paul believed or taught,