Dr. Kenneth Gentry, Jr. clarifies the application of the New Covenant for both the Church and Israel according to clear New Testament teaching, in the following post: https://postmillennialworldview.com/2021/05/14/new-covenant-old-israel-and-the-church/.
The biblical concept of the New Covenant has met with confusion and erroneous teaching today, when it is part of the bedrock of theology for Christianity that Christ instituted during the Last Supper through His sacrifice at the cross. To get this wrong would have major impact on the believer and the church. It is essential for spiritual health that we correctly apprehend this truth taught in the Scriptures.