You do not have an EFI partition so these mount options are not correct. You should unmount them, then try again following the instructions for reinstalling Grub on a legacy/BIOS installation: How to chroot Garuda Linux
sudo mkdir -p /mnt/broken
sudo mount /dev/sda11 /mnt/broken
sudo garuda-chroot /mnt/broken/@
grub-install /dev/sda