OK ISSUE SOLVED. ISSUE was black screen after Vbios update.
Although it seems like GPU bios is the main cause, but there is no issue with ASUS GPU Bios V3.
Main problem is motherboard bios. DONT USE BIOS VERSION 2005
Downgrade your bios version to 1003 by using the Asus Bios Flashback Button at the rear of the motherboard.
1. Download the bios version 1003 to a USB thumbdrive and rename the file
2. Plug the thumbdrive to the rear of the motherboard bios USB port
3. Press and hold the bios flash back button 3 sec and wait for it to flash.
4. Wait for it to be done................... (if not sure refer to your MB manual)
5. Boot into bios, turn off CSM and turn on Rebar.
it's all working now after many days of troubleshooting. When i go into my Nvidia control panel now under system info, rebar show YES.
The black screen issue after Vbios update with rebar enable is caused by the motherboard bios version 2005.
DONT USE BIOS VERSION 2005 this is a beta bios and its buggy AF. It doesn't even allow you to downgrade bios using ez-flash.
Those who having black screen issue and this solved for you. Please post a reply and let us know this solution worked for you.