claim Christianity says that eventually there will be only heaven and hell.
If that is not correct, please tell us 1) where it’s incorrect and 2) what is the correct view.
Prediction: you can’t. — Art48
"Good people go to heaven as a deserved reward for a virtuous life, and bad people go to hell as a just punishment for an immoral life; in that way, the scales of justice are sometimes thought to balance. But virtually all Christian theologians regard such a view, however common it may be in the popular culture, as overly simplistic and unsophisticated; the biblical perspective, as they see it, is far more subtly nuanced than that."
https://plato.stanford.edu/entries/heaven-hell/#:~:text=According%20to%20a%20relatively%20common,of%20earthly%20lives%20we%20live.
From the same article:
"So one way to organize our thinking here is against the backdrop of the following inconsistent set of three propositions:
All human sinners are equal objects of God’s redemptive love in the sense that God wills or aims to win over each one of them over time and thereby to prepare each one of them for the bliss of union with the divine nature.
God’s redemptive love will triumph in the end and successfully win over each and every object of that love, thereby preparing each one of them for the bliss of union with the divine nature.
Some human sinners will never be reconciled to God and will therefore remain separated from the divine nature forever.
If this set of propositions is logically inconsistent, as it surely is, then at least one proposition in the set is false. In no way does it follow, of course, that only one proposition in the set is false, and neither does it follow that at least two of them are true. But if someone does accept any two of these propositions, as virtually every mainline Christian theologian does, then such a person has no choice but to reject the third.[1] It is typically rather easy, moreover, to determine which proposition a given theologian ultimately rejects, and we can therefore classify theologians according to which of these propositions they do reject. So that leaves exactly three primary eschatological views. Because the Augustinians, named after St. Augustine of Hippo (354–430), believe both that God’s redemptive (or electing) love will triumph in the end (proposition (2)) and that some human sinners will never be reconciled to God (proposition (3)), they finally reject the idea that God’s redemptive love extends to all human sinners equally (proposition (1)); because the Arminians, named after Jacobus Arminius (1560–1609) for his opposition to the Augustinian understanding of limited election, believe both that God’s redemptive love extends to all human sinners equally (proposition (1)) and that some of these sinners will never be reconciled to God (proposition (3)), they finally reject the idea that God’s redemptive love will triumph in the end (proposition (2)); and finally, because the Christian universalists believe both that God’s redemptive love extends to all human sinners equally (proposition (1)) and that this love will triumph in the end (proposition (2)), they finally reject altogether the idea that some human sinners will never be reconciled to God (proposition (3))."