It appears the BIOS update for your Asus Tuf B450 is incorrect.
It appears the BIOS update for your Asus Tuf B450 is incorrect.
It's feasible to flash a different version on this MB, even if ASUS disabled the rollback feature in that update. PS: My physically B450 model is why I'm aiming for the right version, but it seems blocked by ASUS's "MB model check." Photos included: Spoiler
Your motherboard appears to be a TUF B540M Plus Gaming. All the BIOS files on your flash drive are for the TUF B450 Plus Gaming. Notice the difference? There's a full ATX version and an mATX version of that board. You can't flash a BIOS meant for one on the other.
The 450m has its own BIOS settings. The version I just downloaded had 'M' in the filename.
Updated the BIOS correctly with AfuEfix64.efi tool (AMI BIOS update). Now the B450 BIOS is functioning and recognizing the AIO Pump.