Yes the land promises were conditional. Israel is a witness and a demonstration to the peoples of the world. God revealed has his plan to us. Will you please give all of Ezekiel Chapters 36-39 some serious study and ask The Holy Spirit to help. These prophecies are yet to see their fulfilment.
People break covenant but God does not. He will restore them for himself and for his good name not for them.
Ezekiel 39
21 ‘I will display my glory among the nations, and all the nations will see the punishment I inflict and the hand I lay on them.
22 From that day forward the people of Israel will know that I am the Lord their God.
23 And the nations will know that the people of Israel went into exile for their sin, because they were unfaithful to me. So I hid my face from them and handed them over to their enemies, and they all fell by the sword.
24 I dealt with them according to their uncleanness and their offences, and I hid my face from them.
25 ‘Therefore this is what the Sovereign Lord says: I will now bring Jacob back from captivity and will have compassion on all the people of Israel, and I will be zealous for my holy name.
26 They will forget their shame and all the unfaithfulness they showed towards me when they lived in safety in their land with no one to make them afraid.
27 When I have brought them back from the nations and have gathered them from the countries of their enemies, I will be proved holy through them in the sight of many nations.
28 Then they will know that I am the Lord their God, for though I sent them into exile among the nations, I will gather them to their own land, not leaving any behind.
29 I will no longer hide my face from them, for I will pour out my Spirit on the people of Israel, declares the Sovereign Lord.
God is going to use Israel to prove to them and the world who he is so that from that time forward no one, neither Jew nor Gentile can doubt his identity or question his holiness.
Ezekiel 36
22 ‘Therefore say to the Israelites, “This is what the Sovereign Lord says: it is not for your sake, people of Israel, that I am going to do these things, but for the sake of my holy name, which you have profaned among the nations where you have gone.
23 I will show the holiness of my great name, which has been profaned among the nations, the name you have profaned among them. Then the nations will know that I am the Lord, declares the Sovereign Lord, when I am proved holy through you before their eyes.