Alright, sorry for my misunderstanding!
Don’t know why it is empty then.
Try generating a new fstab.
sudo mount /dev/sda2 /mnt
sudo mount /dev/sda1 /mnt/boot/efi
sudo genfstab -U /mnt >> /mnt/etc/fstab
You could post the content of the fstab afterwards:
cat /mnt/etc/fstab
Also please post:
ls /mnt/boot