A couple things about the Teaching…
51 I am the living bread[a] which came down from heaven; if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh.”
Jesus tells us He shall or will give His bread for the world. This is in the future tense. Because they see Him, but still do not believe.
60 Many of his disciples, when they heard it, said, “This is a hard saying; who can listen to it?” 61 But Jesus, knowing in himself that his disciples murmured at it, said to them, “Do you take offense at this? 62 Then what if you were to see the Son of man ascending where he was before?[e] 63 It is the spirit that gives life, the flesh is of no avail; the words that I have spoken to you are spirit and life. 64 But there are some of you that do not believe.” For Jesus knew from the first who those were that did not believe, and who it was that should betray him. 65 And he said, “This is why I told you that no one can come to me unless it is granted him by the Father.”
Jesus explains His words are life and spirit before the disciples leave Him. This doesn’t support the opinion that He was merely speaking symbolically. Though we certainly believe His Eucharist is equal to His Spirit and Life! And that it was the Spirit which Jesus came from and fully obeyed. And that His Spirit proceeded from Himself to us.
This is why I asked about Jesus breathing on His Eleven to give them the Holy Spirit later on in John’s book. It was important for God to do so, not only as a symbol but for a reality that His Spirit was delivered to us in fullness through His Son.
Also, there is the connection with Judas who remained with the Eleven, but John points This out here. This is because the moment of His betrayal was at the Lord’s institution of His Eucharist.