Thats what I’m suspecting also, because yesterday there was a big push on firmware transition by Arch, however ptr1337 nicely reverted back from 20250613.12fe085f-6 to the older (but working) 1:20250508.788aadc8-1 version, to temporary solve all firmware related issues (because there were many reports people stuck with black screen and wifi problems and such), so running a paru would be advised if not done since yesterday, to see if your firmwares wanting to properly downgrade back to 05.08 versions, but you can also confirm if you’re using the correct older version by doing pacman -Q linux-firmware and if it outputs 1:20250508.788aadc8-1, then the firmware part should be a-okay.
As a temporary workaround try this (but do a manual snapshot before performing, just in case):
echo 'options snd-hda-intel model=auto' | sudo tee /etc/modprobe.d/asus-audio-fix.conf
Then
sudo mkinitcpio -P
sudo reboot
If that didn’t change anything, then to undo the above changes, either rollback to the snapshot previously created, or delete the /etc/modprobe.d/asus-audio-fix.conf and repeat the last two steps.
Edit: ah nvm, I see you found the solution, while I was typing here 
Glad you find a way, and thanks for sharing the intel.