The Gospels of Matthew, Mark, Luke, and John are not the earliest sources documenting the death, burial, and resurrection of Christ. The scholarly consensus dates these Gospels about 35-65 years after the death of Christ.
Instead, the earliest sources are actually derived from what most bible scholars call the 'creedal passages'. 1 Corinthians 15:3-8 and the long list from Acts, for example, are passages whose material is believed to go back all the way to the 30s AD. Even most critical (i.e. skeptical) scholars concede as much regarding these specific New Testament passages.
In these 'creedal passages', the divinity of Christ, His sacrificial death, bodily resurrection, and post-resurrection appearances are clearly believed and taught by the earliest Christian community (specifically a mere 2-9 years after the death of Christ).
While these extremely early sources do not prove a divine Jesus, they do demonstrate that belief in a divine Jesus was not a product of myth and legendary development over the course of decades and centuries. It was there from the very beginning.