Ephesians 2:15 also speaks of the abolition of the law with its commandments and regulations, which were central to the identity of Israel the nation, and included temple, land and Jerusalem based monarchy. In its place, Christ’s purpose was “to create in himself one new man out of the two”. This was not a restored Israel, as envisaged by OT prophecy, for instance (or any OT expectation for Israel’s future).
From Ephesians 2:19 onwards, the household and temple are built not on restored Israel, but “the foundation of the apostles and prophets, with Christ Jesus himself as the chief cornerstone’.
Paul is not dismissing his Jewish heritage, but the new is not a restoration or continuation of the old. The promises to Abraham, to which the gentiles are now heirs, went beyond the borders of Israel, and beyond anything envisaged by OT prophecy. That’s why Paul describes it as a “mystery” in Ephesians 3, made known to Paul by revelation, but hidden from previous generations. It’s fair to say that previous generations were expecting what you say they now received: a restored Israel. I say that Israel was definitely not restored. The new was just that, not a reworking of the old.
The abolition of the law was necessary because it divided the world into Jews and Gentiles. Of course it had to be abolished so that gentiles could be fully included - not in a new Israel (which is mentioned nowhere, not even in the texts you have quoted), but in “the new man” of Ephesians 2.
I simply don’t see “the underlying assumption in the New Testament … that Gentiles were becoming part of a restored Israel”. I do see however that “Christ became a servant of the Jews on behalf of God’s truth to confirm the promises made to the patriarchs so that the gentiles may glorify God for his mercy” - not to join a restored Israel, but to fulfil the various texts then quoted, including the reign of Jesus “the root of Jesse” whose rejection by Israel the nation proved to be the means by which God’s mercy came to the gentiles outside the nation - not in a restored version of it. There is no “new Jewish empire”, but “members together of one body”, which is now the metaphor Paul uses, replacing Israel the nation.
This is significant, because you have replaced faith in Christ as the basis for universal justification, with faith in what God has done for Israel, which depends on the visibility of a restoration of Israel the nation. I argue that what was visible was the destruction of Israel the nation. In its place was something entirely unforeseen: small groups of Jesus believers scattered across the Roman empire, who subverted the empire from within. Nobody looked at them and saw a restored Israel. Jesus did not foresee a restored Israel, neither did the apostles. The new might employ imagery from the old (temple, the whole building, dwelling place of God), but it wasn’t the old, and one image is notable by its absence, namely a restored Israel.