If
Rev 20 is symbolic of non-existent things (like the millenium) then there is no return of Jesus depicted in the book... which is rather strange, imo.
Also, the idea that no new information can come from the REVELATION OF JESUS CHRIST WHICH GOD GAVE TO HIM is without any scriptural warrant. There is no verse that says "the contents of this book are not suitable for DOCTRINE" or "this book shall not bring anything new to your understanding". Such a rule of interpretation is ENTIRELY and COMPLETELY ARBITRARY, and is designed ONLY to avoid certain obvious truths clearly and UNMISTAKABLY taught by the Apocalypse. The millenium is only one such concept.