And again the context of the passage in question. Context is your key to understanding the Scriptures.
60Therefore many of His disciples, when they heard this said, “This is a difficult statement; who can listen to it?” 61But Jesus, conscious that His disciples grumbled at this, said to them, “Does this cause you to stumble? 62“What then if you see the Son of Man ascending to where He was before? 63“It is the Spirit who gives life; the flesh profits nothing; the words that I have spoken to you are spirit and are life.
64“But there are some of you who do not believe.” For Jesus knew from the beginning who they were who did not believe, and who it was that would betray Him. 65And He was saying, “For this reason I have said to you, that no one can come to Me unless it has been granted him from the Father.” 66As a result of this many of His disciples withdrew and were not walking with Him anymore.
67So Jesus said to the twelve, “You do not want to go away also, do you?” 68Simon Peter answered Him, “Lord, to whom shall we go? You have words of eternal life. 69“We have believed and have come to know that You are the Holy One of God.” John 6:60-69 NASB
If your conclusion is correct then Jesus lied to Nicodemus as there is no mention of the necessity of the RC understanding of the Eucharist.
9Nicodemus said to Him, “How can these things be?” 10Jesus answered and said to him, “Are you the teacher of Israel and do not understand these things? 11“Truly, truly, I say to you, we speak of what we know and testify of what we have seen, and you do not accept our testimony. 12“If I told you earthly things and you do not believe, how will you believe if I tell you heavenly things? 13“No one has ascended into heaven, but He who descended from heaven: the Son of Man. 14“As Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up; 15so that whoever believes will in Him have eternal life.
16“For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life. 17“For God did not send the Son into the world to judge the world, but that the world might be saved through Him. 18“He who believes in Him is not judged; he who does not believe has been judged already, because he has not believed in the name of the only begotten Son of God.
19“This is the judgment, that the Light has come into the world, and men loved the darkness rather than the Light, for their deeds were evil. 20“For everyone who does evil hates the Light, and does not come to the Light for fear that his deeds will be exposed. 21“But he who practices the truth comes to the Light, so that his deeds may be manifested as having been wrought in God.” John 3:9-21 NASB
There are thousands of independent protestant groups, and even more independent protestant individuals who interpret the Bible, which was compiled by the Catholic Church, in many contradictory ways. This is why Jesus left us an authority on earth to interpret Divine Revelation objectively, not subjectively. Best wishes.