After spending quite sometime on the subject, I found out the reason for the RTX3090_V3.exe not update the VBIOS as originally intended.
1. Unpack the RTX3090_V3.exe with 7z (7-ZIP) and you shall find these files inside
2. Open the selected file "Testini.txt" and you shall encounter a cross-refence list of OLD/NEW BIOSes "names" not "number" and this is the main reason for the exe being prevented from working properly.