And I have read Romans 11, enough to know that it doesn't contradict the rest of the bible with regards to apostate Jews. The old covenant was fulfilled in Christ who established a new covenant with His blood. The old covenant no longer exists.
Those who maintain there is a way to please God outside the blood of Christ are not Christians, no matter what they call themselves.
God said that His covenant with Israel would be EVERLASTING. Is God a liar?