Christians are the Spiritual heirs of the Spiritual promises...
The Jews are (still) the physical heirs of the physical promises...
Actually, I’d put it that
Christians are joint heirs with Christ and with Abraham’s blood seed of
ALL
the benefits of the Covenant.
It may well be that vis a vis SOME ceremonial aspects or whatever that blood children of Abraham will have priority. I don’t think so but it wouldn’t rock my theology if it turned out that way.
We are ‘early-horners-in’ on the blessings of the Covenant via CHRIST CRUSIFIED, RESURRECTED AND TREIGNING FOREVERMORE.
But the branch we were grafted into will not be forgotten by a long shot. As Scripture is clear about.
God is NOT slack concerning HIS PROMISES to HIS BUDDY Abraham.
The Jews are (still) the physical heirs of the physical promises...
The first problem you need to overcome is that all the promises were made with Jesus Christ, the "Seed" of Abraham (Gal. 3:16).
Second, your comment above is merely a slogan as it stands. You need a biblical (i.e., non-arbitrary) way to define physical promises vs. spiritual.
The Church has generally made the distinction between the old covenant promises to Israel that were temporary and entirely passed away with the coming of Christ, and those which persist in the person and work of Christ Himself. "Do not think that I came to destroy the Law or the Prophets. I did not come to destroy but to fulfill." (Matt. 5:17)
There are no physical promises to ethnic Israel that persist beyond Christ’s first coming. All the promises terminate one way or another in Christ.