Personal name branding
John, the apostle, had no interest in personal name branding.
As a matter of fact, the book of John refers to the apostle as the “disciple, whom Jesus loved”. As such, John never directly names himself in the book.
The focus of the book of John is entirely on Jesus Christ as God, not on the author whom God chose to write it.
Also, John's relationship with Jesus is emphasized, not the disciple's own personal identity. John understood that it's far better to be beloved of Jesus, than to be him!
Likewise, our identity IN Christ is more important than our own personal name branding!