So the christian claim, the new testament claim, is that Jesus was a priest from the order of Melchizedek.
There is a significant problem with this claim:
The order of Melchizedek, if such an order exists, has no recorded or legal (legal according to God’s law) power to atone for sins.
Only priests biologically descended from Aaron had that power. And the new testament is clear that Jesus didn’t come from Aaron.
The word or title of priest, especially in Hebrew, doesn’t equate to having that power.
So the point of this is that Jesus had no power based on Torah law to use ANY sacrifice, especially the giving of his life, to atone for anyone’s sin.