It’s not Christ’s dying that saves us but His death because the wages of sin is DEATH, not dying.
Leaving Jesus on the cross means that He has not finished the work of redemption that HE said was finished.
If any church thinks that the blood is His real blood, that blood cannot save because it isn’t shed. You are right. Jesus blood, which He needed for this earthly body, is not necessary for His resurrected body because it’s a new body, not His old one. Catholics believe that we get the same bodies as we have now and Scripture teaches against that.
That is a very primitive understanding of Catholic theology. We do not "leave" Jesus on the Cross, but make present in the one Sacrifice.
The cross is a contradiction in every way, like most divine mysteries. It is the vertical symbol of life contradicted by the horizontal symbol of death. It is the Roman symbol of state terror and oppression contradicted by the Christian symbol of victory over death. Those contradictions make sense ONLY when Jesus is superimposed upon them.
The Crucifix, with the Corpus present, is in recognition that it is only through Jesus' suffering and death for our sins that we have our Salvation. It is a reminder that the Mass is not some symbolic recreation of the Last Supper or a farewell meal, it is the divine sacrifice of the Eucharist, a sacrifice of expiation.
Before you dismiss symbols and symbolism as purely Catholic superstitions have you not claimed that the Eucharist itself is symbolic?
Peace be with you