There are some misconceptions about MAD.
First is the idea if two Gospels.
Throughout the Old Testament, at least after Genesis, we have God interacting with His people, the people of Israel, the prophesy is to ‘the Jews’ the circumcised. Beginning in Acts 9 we have the beginning of unavailing the mystery, God had sent Jesus to wash away the sins since Adam; the sins of all people. The Gospel of Mathew begins with a chronology, beginning with Joseph to the House of David. Jesus is culturally the son of Joseph, yet Mathew does not preach another Gospel, one denying Jesus was not begotten by Joseph. The Gospel of Mathew was written to the Jews, and is one of the synoptic Gospels, yet the Gospel of Mark was written to the Romans, also a synoptic Gospel.
For the circumcised, the prophesy is the kingdom to come, where Jesus will sit on the throne of a peaceful would all in peace to the glory of God.
The Gospel of John, is not a synoptic Gospel, it was written to the gentiles, and behind with the eternal presence of the logos, the Word. Jesus is eternal, always present, and had come into the world to fulfill the prophesy, however, more than that, to wash away the sins of Adam, to make one, though faith in the Word to be born again, and blessed-baptized by the Holy Spirit.
It is the why the Gospels are read differently and why of four gospels, Mathew is written to the Jews, John, to the gentiles, Luke to the Greek, and Mark to the Romans, yet all the Gospels contain many similar messages, with the Gospel of John differing some, and may seem to be another Gospel, yet it , as with the other three, all are the good news about the Saviour, Jesus Christ, who came into the world to fulfill the Law, which only God could have fulfilled, and there is the difference.
The mystery, faith in Christ alone saves, yet the chosen people shall also have the prophesy fulfilled.
Two ways of knowing the Gospels.
Paul came for outside the original apostles, Paul was converted by the risen Christ, to carry the mystery to the gentiles. The mystery revealed, all were free though faith in Jesus as the Saviour, and all who believed were able the walk out of the darkness, to be reborn into the Body of Christ.
There is no eventual kingdom, nor events prescribed by the Law, all those in the Body of Christ are saved through Grace, all saved will be ruptured up before the Tribulation; they will be admitted to heaven.
The circumcised have the Law and remain though the times of Tribulation, as they were given the promise by God, where they will inherit the Kingdom on Earth, and eventually rejoice in heaven.
I believe MAD is the outcome if proper Biblical exegeses, and one who rightfully divides the Word of God, shall seek, bay faith alone, salvation. There are no criteria to be born into the Body of Christ, all; including all Jews may be saved by faith alone. The central is the Chosen People have another why to come to God, as this fulfills the prophesy.
Two ways to have eternal life with God.