Bultman considered everything about Christianity to be myth, kosta. In sum, he taught that none of it happened...except that some guy was killed by the Romans.
He sure as heck isn’t gonna think Jesus is the “I am”. In fact, he considered the “I am” to be myth, too.
His scholarship is simply irrelevant.
His beliefs are irrelevant. His argument was not about his beliefs or about "I am" but that John's Gospel was interpolated and he gives concrete, verifiable data, to support his claim. If you think his data are flawed, please provide evidence showing all the concrete examples he lists are wrong.
The first thing an anti-God, anti-Christ activist must do to unsettle a shallow-rooted Christian is to establish the rules of engagement.
Among these is to get the correspondent to accept the presupposition that God is a hypothesis, i.e. he constructs a strawman "god" to debunk. More importantly, by doing this he puts the shallow-rooted Christian in his own shoes, he gets him to see things through an atheist/agnostic lens.
From that observer perspective he can amplify any doubts that linger in the mind of a shallow-rooted Christian.
Another rule of engagement is the language itself, what the words shall mean and what words are to be allowed.
Chief among these words are the Names of God, e.g. I AM, for the hypothetical strawman "god" must not be personified in any sense. He must reduce the "Who is God" to a "What is 'god'."
And among the terms he must control are reality and objective truth. Both must be discernible by naturalist means, i.e. sensory perception and reasoning. If it cannot be discerned that way, under his rules of engagement, it goes into the "only knuckle-draggers swallow this" side of the table.
He demands that all words in the debate be universal in significance, meaning and usage. Anyone - whether atheist/agnostic or Christian - must receive the same words the same way, i.e. no difference between the words of a hypothetical "god" and the words of men and no difference between Christian and agnostic/atheist.
Anything that cannot be proven by empirical test or observation or logic is sorted to the knuckle-draggers side of the table. And of course spiritual discernment is not allowed at all.
By doing this, he makes his strawman "god" into a hypothetical man. He anthropomorphizes God into a small "god" a mortal can comprehend.
But naturalist means will not do.
For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God. For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent.
Where [is] the wise? where [is] the scribe? where [is] the disputer of this world? hath not God made foolish the wisdom of this world?
For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe.
For the Jews require a sign, and the Greeks seek after wisdom: But we preach Christ crucified, unto the Jews a stumblingblock, and unto the Greeks foolishness; But unto them which are called, both Jews and Greeks, Christ the power of God, and the wisdom of God.
Because the foolishness of God is wiser than men; and the weakness of God is stronger than men. - I Corinthians 1:18-25
Doubting Thomas was an Apostle, too.
But I will not play by the anti-Christ's rules of engagement because God is not a hypothesis. He lives. His Name is I AM. I've known Him for a half century and counting.