True Israel is Israel, gentiles in the church get to be grafted in to Israel, increasing Israel, but the church is not Israel.
Israel will be restored to its fully promised extent which is all of the current state of Israel, the West Bank, Gaza and southern Lebanon.
Prophecies of the new Jerusalem point to a larger dispensation. God has not forgotten Israel or their role as the chosen people, but the call to salvation must end with the Kingdom and a new Jerusalem which symbolizes the wider covenant, in other words, the Christian faithful will also be a chosen people and have their realm on the earth.
This suggests to me that the new Jerusalem will be in a physically different location from the old Jerusalem but this does not mean that promises made about Jerusalem are now invalid.
In this dual fulfilment of prophecy, Jews and Christians will be fully reconciled because there will no longer be any theological differences as the returned Jesus will be known as Messiah to both.
Not only do I believe this to be true, I believe it to be fairly imminent and political developments point towards this outcome. Since we have the same enemies, we could reasonably expect the same blessing.