The reason for this is that there really is just one good news. That news is the gospel of Jesus Christ. Simply put, it is Jesus Christ and him crucified.
In I Corinthians 2:2 Paul writes, "For I decided to know nothing among you except Jesus Christ and him crucified." While profound in nature, the gospel is quite simple. Ultimately it comes down to the willing sacrifice of Jesus Christ on behalf of his followers. It is him in our place on the cross.
When we talk about the gospel we can discuss various aspects of it such as the kingdom of God, the substitutionary atonement, the impeccability/peccability of Christ, God's sovereignty/man's responsibility, what faith means, the penal nature of Christ's sacrifice, OT prophecies fulfilled, the meaning of "It is finished!", etc. These are all wonderful things to understand and grapple with. HOWEVER, they are not things to divide over.
The gospel is a unifying, rallying point for Christ's church. We have a simple message to rejoice in and proclaim. We take deep joy in the truth that we have been saved from our sins by Jesus Christ. This is something that cannot be overstated. To ponder this is to be stunned. We have also been commissioned by Christ to take this good news to all peoples.
The task we have been given is immense. We will never succeed in proclaiming the gospel to all nations if we are fractured in doing so. there's no reason for any fracture to exist if we realize that we have one and only one message. As the body of Christ we can and should be able to come together quite easily around the gospel. When we grasp this fact, the details of our working together become just that: details. They are no longer stumbling points.
Let's embrace the good news of Christ crucified as a unifying factor for the church.