Oh my, there is so much more that you have not been taught! When God says tetelestai, He measn all of it. He laid His Life down at that Cross for you and for me. He paid the penalty for our not having the righteousness required to enter God's Presence. He did that once, for all, forever. He told His disciples to brake bread together in remembrance of His coming act of exoneration for them and you. His blood was shed out upon the ground there. He followed the commandment to take a portion of the precious blood tot he Mercy Seat and sprinkle it there, there upon the Heavenly Mercy Seat for you and me, to cover the law of sin and death so the Sacrifice need never be repeated, He accomplished it all, once, for all, forever. So with that covering of the Mercy Seat above the law of sin and death you can immediately have God's Life in you to raise the Born from Above up in the Way that they should go. Had He withheld His blood from the Mercy Seat, the lambs and goats and bullocks would have still been required to atone for the sin of we fallen descendants of Adam.
Learn the lesson of the 300 into whom the Holy Spirit entered at Pentecost. Learn the lesson of the Gentiles in the house of Cornelius into whom the Holy Spirit entered even before Peter finished preaching, because it is by faith, the belief that Jesus is Savior and Lord, that Justification comes to the unrighteous. There is no righteous in the man or woman who has not the Life of God in them. But God's Grace offers His Life to immediately be yours, if you will but believe and walk in His Spirit.
What was finished was not a new Passover, for the 'Old Passover' was not gone away. what was finished was a new Covenant relationship between Man and God, hallmarked by God's righteousness available because Jesus paid the penalty we owe. Jesus fulfilled the Times of God to open the Life of God to all who will come by simply believing God in His Astonishing Grace to them.
Please do not mistake your own private interpretations of Scripture with Scripture itself. In the Bible Jesus said "This is my Body" and "This is my Blood." He gave his disciples the command to do this in memory of him. Nowhere in Scripture does it say that it is anything other than his Body and Blood. All you have presented are human rationalizations to deny what our Lord actually said. So much for sola scriptura.