How can Paradise be domed, with its highest and most spacious part being Firdaus, even though a dome implies constriction the higher it gets?

What Ibn al-Qayyim mentioned, that Paradise is domed, we do not know of any legal basis for it. Rather, it was said about the 'Arsh (Throne). Some have used the Hadith of Jubayr ibn Mut'im as evidence that the 'Arsh is domed, but the Hadith has a weak chain of narration. Even if it were authentic, it does not indicate that Paradise is domed. The authentic Ahadith have indicated that the 'Arsh has legs and bearers, and delving into these unseen matters without clear evidence should be avoided.