The Rashbash has an interesting responsum (no. 436) regarding the belief that the world will eventually be destroyed. Noteworthy is his conviction that the Bible and the Talmud explicitly teach that the world will be destroyed but still tells his respondent that since this is not a fundamental belief he can believe whatever he wants:
Regarding what you said about whether the world will be destroyed or not, and that your view is that it will not, and that you condemned those who say that it will and consider them to be ignorant fools. What will we do since this is the view of the Sages? They said, "The school of Eliyahu taught: The world will be for six thousands years and then destroyed for a thousand, as it says 'And the Lord alone will be exalted on that day' (Isa. 2:11)." This is mentioned in a number of places by the sages (Rosh Hashanah 31a; Sanhedrin 97a; Avodah Zarah 9a). And if the Rambam (Moreh Nevukhim 2:28) does not share this view and explains the explicit verses according to his approach, the Ramban (Kisvei Ha-Ramban, vol. 1 pp. 159-160) relies on the words of the sages and agrees that the world be destroyed.Yes, the Rambam does take the opposite view, so there are sages on either side of the debate. But the Rashbash thinks that the Rambam rejects the talmudic and scriptural view on this subject and still allows it.
And know that one who believes that the world was not created contradicts the Torah, and every Jew is obligated to believe it. But whether or not it will be destroyed in the future does not damage one's beliefs as long as one agrees that God has the ability to do this and that it depends on His will. Just like he created it from absolute nothing he can destroy it. His ability is even more evident from His creating it than from His dismantling it.
A verse that teaches this [the eventual destruction of the world] and cannot be explained otherwise is: "Of old You laid the foundation of the earth, And the heavens are the work of Your hands. They will perish, but You will endure; Yes, they will all grow old like a garment; Like a cloak You will change them, And they will be changed. But You are the same, and Your years will have no end." (Ps. 102:26-28) Therefore, everything in existence will perish except for the True Existent whose existence is necessary. And even though there are commentators who explain "They will perish" as meaning if God so desires, and others explain it to refer to specifics, these are forced because according to these explanations why would it say "But You are the same, and Your years will have no end" if the heavens will exist forever... Therefore, what is revealed from this verse is the truth according to my view, but you believe whatever you want.