I'm glad we agree.
So back to the 7 Churches in Revelation that believe in Christ. How are they not the body of Christ?
No disagreement, that many Jews tried to get the Gentiles circumcised and to obey the Law of Moses in order to become a part of God's people after the Cross. That, as you have pointed out, is evidenced in the book of Acts.
But this doesn't address my 2nd point. Are God's people (the church) now under the old covenant or new covenant?
Romans 7:4 Likewise, my brothers, you also have died to the law through the body of Christ, so that you may belong to another, to him who has been raised from the dead, in order that we may bear fruit for God.
Hebrews 8:13 In speaking of a new covenant, he makes the first one obsolete. And what is becoming obsolete and growing old is ready to vanish away
Galatians 4:30-31 But what does the Scripture say? “Cast out the slave woman and her son, for the son of the slave woman shall not inherit with the son of the free woman.” So, brothers, we are not children of the slave but of the free woman.