“that what was promised to Abraham was the kosmos, the world.”
That’s nonsense. The promise in Romans 4:13, “For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith” refers to the promise to Abraham in Gen. 12:3, “And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed”.
The heir referred to is Christ Gal. 3:16 “To thy seed, which is Christ”. Christ is the heir of the world, (Rev 11:15) “…The kingdoms of this world are become [the kingdoms] of our Lord, and of his Christ; and he shall reign for ever and ever”, the ends of the earth are his possession and it is in him that Abraham and we are blessed.
But the promise of blessing was only one of the promises to Abraham; there still remains the promise of the land as an eternal inheritance.
Paul in Romans 4 does not limit the promise to any particular aspect of God’s covenant with Abraham, so I suspect The System® is forcing you to your conclusion.
But Romans 4 says that Abraham would be the heir of the world. In fact you admitted the promise was to Abraham. Now, we know that ultimately applies to Christ, who is the Seed to whom the promises were made. And we also know from Hebrews 11 that ultimately it is a spiritual promise and fulfillment in the “better country” that God is preparing for all His people (not just the Jewish remnant).
The bottom line is that you have absolutely no basis for dividing the promises to Abraham/the Seed along the categories dictated by The System®.