The New Covenant & The Church - 1

Jeremiah and Ezekiel extend the promise of a New Covenant and all its blessings & provisions to national Israel, yet Isaiah hints that its blessings would also encompass the Gentiles (per the Abrahamic covenant), and the New Testament confirms that the Church can claim the promises of the New Covenant.

But whereas the Jews can claim all of its promises, the Church can only claim some of them. Which promises & blessings of the New Covenant can the Church claim, and why?