If the four Gospels matched word-for-word, skeptics would (rightly) call it collusion. The fact that they overlap massively on the core and diverge in small detail is what historians call independent attestation.
What they agree on
Jesus' baptism, miracles, teaching with authority, conflict with religious leaders, the Last Supper, crucifixion under Pilate, empty tomb, post-resurrection appearances, and the claim to be uniquely God's Son. The skeleton is identical.
What looks like disagreement
Different angels at the tomb (one mentioned vs. two), different orderings, different details emphasized. J. Warner Wallace — a cold-case detective — notes these are textbook signs of genuine eyewitness testimony, not fabrication. Police interviews of real witnesses always vary on peripheral detail; fabricators iron things flat.
Four faces, one Christ
The Fathers, drawing on Ezekiel 1 and Revelation 4, saw the four Gospels as the four living creatures: Matthew the man (genealogy), Mark the lion (royal urgency), Luke the ox (sacrifice), John the eagle (divine vision). St. Irenaeus argued in the 180s that four is exactly right — the gospel reaches the four winds.
A pastoral word
You don't need to harmonize every Synoptic chronology before trusting Christ. The disciples didn't. They saw him, heard him, ate with him after he rose — and then they wrote it down, each in his own voice. That's why the Church receives four Gospels, not one flattened summary.