Hello, the update should take roughly 15 to 20 seconds and prompt you when completed. Make sure there are no other applications running in the foreground or 3D applications running when running the update tool. If GPUZ is showing the correct VBIOS then the update must have been completed successfully.
13900KS / 8200MT CAS36 / ROG APEX Z790 / ROG TUF RTX 4090