I expected that much ![]()
First exit the chroot but keep the mount
Also mount your efi partition - I see there is one
mount /dev/sda1 /mnt/boot/efi
I would check if the package lists in the /mnt is intact - then sanitize them and use them to a complete rebuild of the filesystem.
Using these as command templates
If the original files are intact (/mnt/rootfs-pkgs.txt & /mnt/desktopfs-pkgs.txt)
pacman -Syy --needed --root /mnt $(cat /mnt/rootfs-pkgs.txt | awk '{print $1;}')
pacman -Syy --needed --root /mnt $(cat /mnt/desktopfs-pkgs.txt | awk '{print $1;}')