The problem with Elihu
From the comparison of Job 1:1 (where Job is called by the narrator תָּם [perfect] and יָשָׁר [upright]) and Job 36:8-9, where Elihu implies that "Job suffered because he sinned arrogantly", Tony Chan, in his Answer, concludes that "Elihu contradicted the narrator".
Elihu, a young and presumptuous man, frustrated at the ineffectuality of the speeches of Eliphaz, Bildad and Zophar, stands up with his four moralistic speeches (Job 32-37), which are nothing but an even more emphatic rehash of what the older "friends" have inconclusively attempted to oppose to Job. The "center-piece" of Elihu's moralistic discourse is the "educating value of suffering” to which God submits man, but man is stubborn and does not heed God (“For God speaks, the first time in one way, the second time in another, though a person does not perceive it." – Job 33:14).

Job and His Friends, Gustave Doré (1832-1883)
The problem with Elihu is that he has been traditionally seen, in spite of his youth, as someone who manages to show Job wrong, whereas the older "friends" (Eliphaz the Temanite, Bildad the Shuhite and Zophar the Naamathite), have failed.
Elihu, a young and presumptuous man, frustrated at the ineffectuality of the speeches of Eliphaz, Bildad and Zophar, stands up with his four moralistic speeches (Job 32-37), which are an even more emphatic rehash of what Eliphaz, Bildad and Zophar have inconclusively attempted to oppose to Job. The "center-piece" of Elihu's moralistic discourse is the "educating value of suffering” to which God submits man, but man is stubborn and does not heed God (“For God speaks, the first time in one way, the second time in another, though a person does not perceive it. – Job 33:14).
Eventually YHWH God intervenes directly (Job 38 - 42) and speaks directly to Job, simply ignoring everything that the pretentious Elihu has said, and with some majestic images of his creative power, shows to Job how his counsel is too much above man's limited understanding for man to contend with God.
Job briefly intervenes, first to humble himself and declare how foolish of him it was to speak at all (“Indeed, I am completely unworthy – how could I reply to you? I put my hand over my mouth to silence myself. I have spoken once, but I cannot answer; twice, but I will say no more” - Job 40:4-5).
Then, at the end of the Divine Speeches, when Job realizes that, while he has said nothing wrong, and has no specific fault for which his misfortunes should be considered God’s “punishment”, still he is, and should behave like a humble creature of God, and yield to God’s omnipotence and inscrutable ways.
1Then Job answered the Lord: 2“I know that you
can do all things; no purpose of yours can be thwarted; 3
[you asked,]‘Who is this who darkens counsel without knowledge?’ But I
have declared without understanding things too wonderful for me to
know. 4 You said, ‘Pay attention, and I will speak; I will
question you, and you will answer me.’ 5 I had heard of you
by the hearing of the ear, but now my eye has seen you. 6
Therefore I despise myself, and I repent in dust and ashes! (Job
42:1-6, NETBible)
In the he Epilogue (42:7-17), YHWH condemns Eliphaz, Bildad and Zophar and, at the same time, explicitly approves Job’s words.
Conclusion
The interpretation of the real purpose and meaning of the Book of Job, of how it “solves” the problem of human suffering, depends to a large extent on the role and meaning attributed to “The Speeches of Elihu” (Job 32-37)
Far from giving the right key that allows men to understand and accept a presumed “redemptive function of suffering”, “The Speeches of Elihu” are first simply ignored by YHWH God in the Divine Speeches (38 - 42), then, in the Epilogue, they are, again, totally ignored by YHWH God.