I believe the Gospel is the gloriously good news, indeed the very best news, that God has graciously done everything necessary, at great sacrifice to himself, through the sinless life, penal substitutionary and sacrificial death, and bodily resurrection of Jesus Christ to reconcile us to himself forever.
So, yes, the gospel is primarily about restoring the ruptured relationship between man and God. That is the essence of the gospel. But there are many things entailed by the gospel. I thus make a distinction between the content of the gospel and its consequences. The consequences, or those things entailed by the gospel, are racial reconciliation, ministry to the poor and homeless, the final redemption and cleansing of the material creation in the new heavens and new earth, and the universal application of justice in all human affairs. But I remain firmly persuaded that we have not preached the gospel until we have made known the way in which a fallen, rebellious sinner might be reconciled to God, forgiven of their sins, and granted entrance into the kingdom of Christ Jesus.
So, at the heart of the gospel is the good news that God has made it possible for us to escape the condemnation of hell and the wrath we otherwise so richly deserved to endure.