Is it considered disbelief to believe that some prophets were tormented and tested more than others, or to question the wisdom of creation and not be convinced by the answers, and what is the solution for the obsessive thoughts and intellectual confusion that lead one to wish for death?

It is not wise to elaborate on refuting whispers (waswas); rather, it suffices to state generally that these whispers do not harm or affect the soundness of faith, as long as you dislike and flee from them. This is proof of sincere faith. The advice is to turn away from these whispers, ignore them, and pay no attention to them. You are on goodness as long as you strive against them and seek to rid yourself of them, and you are hoped to receive reward and recompense. You are upon Islam and do not depart from the religion because of them, so continue to strive against them and push them away from yourself.