You made a claim of truth. The burden of proof is on you.
Oh?
"He took from among creation that which is bread, and gave thanks, saying, 'This is my body.' The cup likewise, which is from among the creation to which we belong, he confessed to be his blood. He taught the new sacrifice of the new covenant, of which Malachi, one of the twelve [minor] prophets, had signified beforehand: 'You do not do my will, says the Lord Almighty, and I will not accept a sacrifice at your hands. For from the rising of the sun to its setting my name is glorified among the Gentiles, and in every place incense is offered to my name, and a pure sacrifice; for great is my name among the Gentiles, says the Lord Almighty' [Mal. 1:10–11]. By these words he makes it plain that the former people will cease to make offerings to God; but that in every place sacrifice will be offered to him, and indeed, a pure one, for his name is glorified among the Gentiles".
-- Irenaeus, Against Heresies 4:17:5 [A.D. 189]
So Irenaeus is one Church Father who believed in the Real Presence. And that was obviously long before this nonsense claim of yours about 300 A.D. or whatever.
Another one is St. Ignatius of Antioch.
"Take note of those who hold heterodox opinions on the grace of Jesus Christ which has come to us, and see how contrary their opinions are to the mind of God. They abstain from the Eucharist and from prayer because they do not confess that the Eucharist is the flesh of our Savior Jesus Christ, flesh which suffered for our sins and which that Father, in his goodness, raised up again. They who deny the gift of God are perishing in their disputes."
-- Ignatius Of Antioch, Letter to the Smyrnaeans 6:2–7:1 [A.D. 110]
St. Ignatius was a student of St. John. If St. Ignatius is wrong about his understanding of Our Lord's body and blood, well, where did he get this wrong idea from? Did St. John teach St. Ignatius error?
Two people, whoop-de-do, that's not counting the countless others who might have had other opinions, right...? Other "students", etc...?
And that's beautiful nonsensical twisting of scripture combined with man's words in that first paragraph, etc...
I'll ask you again, why is there absolutely no mention in the NT scriptures after Jesus about any kind of "transubstantiation" regarding communion at all, etc, "AT ALL", if they supposedly taught it or thought it was very important, etc...? Why, why, why...? No mention at all whatsoever... Why...? Or "why not", etc...? Especially if it is or was that important, etc...? I think there would at least be some mention of it if it was, etc... Or maybe, maybe there is no mention of it at all, cause they didn't even have those kinds of thoughts about it, now there's a novel thought or idea, right...?
Anyway, it was to "remember"... And things that are done or made or put into place to "remember" "another thing", usually mean "another thing", etc...
And I already tried to explain to you that his body or the bread is the Word of God, when Jesus talked about being the Word and the true bread that came down from heaven meaning the Word, or his words, etc, was his body, etc, and his blood, the Spirit, etc, recall that other people thought Christians were "drunk" when they were "full of the Spirit", or the Spirit fell down upon them, etc, it's also "fire", etc, and part of partaking of the wine or the blood was also spiritually symbolic of the baptism by fire or the Spirit, etc...
But people who want to take everything literally never understand anything symbolically or spiritually...
That a physical thing could mean something else in a spiritual sense just falls on deaf ears with them...
And it's not as if there is or was not plenty of that in the Bible right...? almost all physical things only being a "shadow" of things spiritually...? The true meaning of the thing being in it's symbolic or spiritual meaning, or it's spiritual reality, etc...?
Anyway,
Anyway, I'll even go so far with you that "even if" the bread was to be His literal flesh or physical body, and the wine his literal blood, He made it pretty clear that even those things were to parish and pass away, and were only a "shadow" or "shadows of" the "Word or Words of God" and the "(Holy) Spirit of God", etc, only "a shadow", etc, and those two latter things are the two things of most primary importance, etc...
And that is also what those things were to "truly mean you were "eating and drinking" and/or taking in", etc, making His physical flesh and blood of no importance since those things perished and went away when He did physically, but the Word and the Spirit are eternal and lives on, and are what we are to see ourselves "eating and/or drinking and taking in, partaking of", etc, when we have or do communion, etc...
God Bless!