There are several truths from God's Word that have not been taught in relation to Christian Zionism aka Dispensationalism. The restoring of the Tabernacle of David is one of them.

At the Jersusalem Council in Acts 15v15 James quoted from Amos 9v11-12 'On that day I will raise up the tabernacle of David which has fallen down and repair its damages; I will raise up its ruins and rebuild it as the days of old'.
The tabernacle of David as James shows that this was the coming together of Jew and Gentile in union with Christ Jesus who is the true David whose kingdom is forever.

God said to David that a Son and a King will sit on his throne forever. Christian Zionists and Dispensationalists wrongly assume that the Jews are still in covenant with God and returning to the land of 'Zionist' Israel fulfills prophecy, one of them being Amos 9v14 'I will bring back the captives of My people Israel'. But this ignores the context of the tabernacle of David.
How could God accomplish all His promises to Israel if the Northern Kingdom was in captivity and the ten tribes of 'Israel' became 'lost'?
The New Covenant fulfills God's promises to unite the house of Israel with the house of Judah (Jeremiah 31v31f) because in this passage in Jeremiah 31 God said He would make a 'New Covenant' with the house of Israel and with the house of Judah.
This is not exaclty a grey area that is ambiguous and difficult to understand. God will make a NEW Covenant with the house of Israel and with the house of Judah.
Jews and Gentiles united to Christ have been brought into the New Covenant. So there is NO division between physical Israel and the Church. We are all one in Christ Jesus who is the 'One Shepherd over them the true David' who will raise again the true tabernacle of David-the Church.
That is not Replacement it is obviously Fulfillment. But the father of lies has invented this false misnomer 'Replacement' theology.
The word 'Forever' in relation to God's covenant with both Abraham and David refers ONLY to the New Covenant. The Old Covenant ended in AD70 when God poured out His wrath on Israel as He said He would...'the people of the prince who is to come shll destroy the santuary, the end of it shall be with a flood and till the end of the war desolations are determined' (Daniel 9v 26)
The Jews returned to the true 'land' the New Jerusalem by believing on Christ the true David who is the head of the Bride the true Tabernacle of David. Jews who believed in Jesus in the first century, as James understood from Amos was the fulfillment of the prophecy that 'I will bring back the captives of My people Israel'.