I just got an ASUS Zenbook 14 and installed Fedora, but on boot the function row on the keyboard works as F1-F12, rather than as volume/media and other system function keys. I went into the UEFI and found the only option to customise is to just completely disable media keys and then stumbled upon this forum thread (link) from the Linux Mint forums with a fix that I have adapted for Fedora below.
On Windows you can apparently configure this behaviour in the ASUS utility GUI, but on Linux it can be changed via the ASUS WMI driver parameters in a configuration file in /etc/modprobe.d
sudo nano /etc/modprobe.d/asus_wmi.conf
Then paste in the following
# Enable media playback keys/set fn-lock on boot options asus_wmi fnlock_default=N
Lastly regenerate the initramfs with dracut to incorporate the change we made and then reboot to test. This is the major area where this guide diverts from the Linux Mint thread since Mint doesn’t use dracut (yet…).
sudo dracut -f && sudo systemctl reboot