All your subvolumes are there, but for some reason the garuda-chroot tool is not correctly setting up the mounts for them. You will need to mount them manually and just use arch-chroot instead.
Exit out of the chroot if you are still in it, then set it up by specifying each mount point like this:
sudo mount -o subvol=@ /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt
sudo mount -o subvol=@home /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt/home
sudo mount -o subvol=@root /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt/root
sudo mount -o subvol=@srv /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt/srv
sudo mount -o subvol=@cache /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt/var/cache
sudo mount -o subvol=@log /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt/var/log
sudo mount -o subvol=@tmp /dev/mapper/luks-f2314da2-7bb3-4bfa-83ba-9a58d102e216 /mnt/var/tmp
sudo mount /dev/nvme1n1p1 /mnt/boot/efi
arch-chroot /mnt
Once you are inside the chroot try updating your system again.