Shticky,
As you know, Tzion refers to either of the three that you’ve mentioned: J-m, Har Habayis, Bais Hamikdash, depending on the context.
In Nach VERY, VERY often a posuk seemingly repeats itself, almost poetically, and we learn from the different nuances.
. ????? ??????? ???????, ????: “???? ???? ?????, ??????? ????”, ?????. …(Shulchan Aruch Orach Chaim 561:1 as quoted from Yeshayahu 64:9)
One who sees Jerusalem in its destruction says: “Tzion has become a desert, Jerusalem desolate” (Isiah 64:9), and rips
BTW, there is a meforush who says that in Acharis Hayamim, the entire world will become E”Y and E”Y will become Y-m, so in that time it may very well be that E”Y will become Tzion.
This requires more iyun be”H.