Built-in speakers in monitor not recognised and not working after updates

Support Sound
22

You should consider updating BIOS for this motherboard

Asus website is showing 13 BIOS updates released since the version shown on your system
https://www.asus.com/Motherboards-Components/Motherboards/All-series/TUF-B450M-PLUS-GAMING/HelpDesk_BIOS/