The Catholic Eucharistic doctrine is a fulfillment of Old Testament “types” which foreshadow the gift of God in the Eucharist.
For example,
In the first Jewish passover meal, the Jews did not eat a symbolic representation of the lamb that was slaughtered, they ate the real thing.
Among the temple sacrifices (described in Exodus/Leviticus) there was one where the sacrificial animal brought by a “sinner” was sacrificed, cooked, and then even partly eaten on the spot. They ate not a symbolic representation of the sacrifice, they ate the real thing.
So
Jesus could have instituted the Eucharist anytime he wanted to, but he chose the Apostles’ passover meal, to link that meal and the new covenant to the old one and to fulfill the typology and establish the new passover in his own body and blood.
The Old Testament eschewed idols and representations, in general. So, Jesus in the Eucharist is the Real Deal, to use a 21st century idiom.
“Refute” is a good word, it’s used in the Bible. but, have no fear, you have the truth on your side.