To begin the author of the gospel of John appears to be a Pharisee, his testimonies have more Pharisee private conversations and meetings then anything else.
It also represents Yeshua as an Egotistical law breaker, which too many may be confusing Yeshua with, as this is what most have chosen to be their "jesus", when it can be proved entirely not his wording.

One of the clearest is the point he made "do not go after those who say "I Am" EGO I-Mee pretending to be Yeshua"....

So when we have "I (EGO) am (I-Mee) the Bread of life (eat me)", "I (EGO) am (I-Mee) the way truth life", "I (EGO) am (I-Mee) eternal life" etc...

This is like a rusty bucket with too many holes in....
God is I (EGO) Am (I-Mee) Biblically and scientifically (will show)...

So it is basically defiling the law and making Yeshua look like a dragon, which is to say anything made the river, other then God.

Next point it uses is third party in Yeshua's own speeches, about him self.

The testimony mismatches each other, to Yeshua's words in the other remaining gospels x3:

Destroying of the temple is said to be made up by the Pharisees in Matthew and Mark, yet in John it is told as Truth by a Pharisee.

The disciples were told to go to the lost sheep of Israel, John says go to all nations.

Eternal life comes from giving up wealth; John says it comes from Yeshua and life is more abundant, as you drink.

Yeshua said only drink water, the wedding and wine only goes to deceive.

Yeshua said all knowledge is from his father, John says Yeshua is the father.

Yeshua said anyone who blasphemes the Holy Spirit will be not forgiven; John said Yeshua will send the Holy Spirit, when it has always been throughout the bible.

Lead up to Pilate silently; in John it has been an elaborated to an "I (EGO) am (I-Mee)" conversation with Pilate.

Loads of Old Testament points:

The list could be added, yet basically it defiles the Old Testament so much it is deliberately to put people off Yeshua as being anyone (if understood), yet this has done the opposite, due to the deception.

For those who know the Bible; Revelations speaks of the fake Anti-Christ church that teaches eating of things unclean (eating and drinking Yeshua's flesh and blood), Harlotry (Worship anything other then God) and Balaam teachings (God does not sacrifice).

This is not a complete list as too do that, would mean literally every word in the gospel of John Nicodemus (Nicolaitans) proven false.