How can the Almighty's saying, "And We granted not to any human being before you immortality" (21:34), be reconciled with 'Isa (Jesus), peace be upon him, being alive and raised to heaven?

Immortality in this world is not for any human being. Allah Almighty mentioned in the Qur’an that every soul shall taste death, and that the prophets, too, shall die. Jesus, peace be upon him, despite being raised to heaven and living there, will die before the Day of Judgment, as stated in His Almighty saying: (And there is none of the People of the Book but will believe in him before his death. And on the Day of Resurrection, he will be a witness against them) [An-Nisa: 159]. Jesus will descend before the Day of Judgment to kill the Dajjal, break the cross, and establish justice. The duration of his stay after his descent ranges between seven years and forty years, according to narrations, after which he will die, and Muslims will pray over him. This period, although long compared to the lifespan of an ordinary human, is a limited period and not eternal immortality.