You are ignoring the fact that in the course of the discourse in John Six, most of the crowd abandoned Jesus precisely because they took his words literally, and were horrified, and he did not call them back to explain that he was using a metaphor.
If your theory that the language about his body and blood was metaphorical is true, then Jesus was a lousy preacher. In fact, he was a DECEPTIVE preacher. By his inept preaching, he drove people away from himself, and thus to damnation.
I suggest that you reread John 6. Jesus answers their concerns about what He said. He repeats that only God can save and choose. This is a huge contention today. People cannot accept that it is God who does the choosing, not man. They think that this makes God unjust. Read the whole chapter again without prejudice. The people that left Jesus He already determined to be unbelievers who would not believe. They followed Him because they thought they could get fed food for nothing.
John 6:26 Jesus answered them and said, Verily, verily, I say unto you, Ye seek me, not because ye saw the miracles, but because ye did eat of the loaves, and were filled.
35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
John 6:36 But I said unto you, That ye also have seen me, and believe not.
Jesus plainly taught that it was by coming to Him and believing that one was saved. It wasn’t by anything else at all.
40 And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day.
John47 Verily, verily, I say unto you, He that believeth on me hath everlasting life.
Again I ask you by the mercies of God to reread John 6 without prejudice.