> Could you try to update the BIOS if available? It might fix something.
The BIOS is already updated to the most recent version.
Also, I don't know if this is of any use but I've been reading about this issue
from other people with the same problem and apparently built-in audio sometimes
comes back after booting into windows from an external SSD, restarting, then
booting back into Linux. I'm yet to test this.