Does the ASUS TUF GAMING B450-PLUS support Ryzen 5000 processors?

Yes, but only after a BIOS update. The board natively supports Ryzen 1st, 2nd, and 3rd gen chips plus 4000 G-Series APUs, but Ryzen 5000 requires a firmware flash — a common retrofit that extended B450 boards’ relevance well past their original lifespan.