From live USB:
sudo mount /dev/nvme0n1p5 /mnt
sudo garuda-chroot /mnt/@
When into chroot (you are root and don't need sudo there)
mount /dev/nvme0n1p2 /boot/efi
grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=garuda --recheck
update-grub
At the end exit from chroot
exit