the odds are good that Gigabyte made a backdoor into your system to update their bios... as this assumes Windows regedits that no longer work in W11 that would be why there is no update and also 1 possible reason the system bluescreens
yes replacing the motherboard = you may as well just replace the system so a better fix tends to be finding a stable setup and sticking to it... which in this case is prob the OS build that was around at the time the motherboard came out so that means saying off line [not ideal for a gaming rig] or locking out updates [takes high networking knowledge]
my advice is save up for a new system
