That's correct. The Covenant is with the Jewish people and Jewish people only, and cannot be abrogated or annulled, replaced, or "made obsolete," as the Christian book of Hebrews (Ch. 8) suggests. The Covenant God made with Israel is an everlasting covenant; the Torah is to be observed forever, and therefore cannot be "fulfilled."
God also made an everlasting Covenant with the Gentiles after the Flood. Therefore a "new covenant" proposed by Christians is in conflict with God's everlasting covenant made to Noah. The Gentiles have been given the Noahide laws and that's where their obligation and dealings with the God of Israel ends.
I believe I understand where you are coming from but perhaps not completely. It appears you are Jewish but also might be part of the Noachide sect?
(Jer 31:31 KJV) Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah...
What must be distinguished here are the TWO different houses and the TWO different peoples.