Your system is fine and the BIOS update succeeded. That underscore cursor means the system is doing one final hardware check, and the VGA LED probably means the BIOS didn't detect a display from the GPU's DisplayPort or HDMI ports, and you're probably seeing the underscore cursor from a DVI or VGA output ...
This is because your previous BIOS defaulted to CSM Mode and after October 2022, MSI changed the default to UEFI Mode in all BIOS updates. UEFI Mode prioritizes DisplayPort and HDMI and ignores DVI and VGA. CSM Mode is the opposite - it prioritizes DVI and VGA first, and HDMI and DisplayPort dead last. Since your system is now in UEFI Mode, the VGA LED is triggering because it can't find a display panel hooked to DisplayPort or HDMI but your getting the underscore cursor. That means the system is waiting for you to connect a DisplayPort or HDMI cable to the GPU. Once you do, the VGA LED will go off and the system will POST as normal ...