Oh, I do use genfstab.

I am doing this manually for educational purposes.

EDIT: I have been following the installation guide on a vital machine prior to my Windows malfunction. Among the partition examples I saw ones that have root and efi partitions mounted in a non-nested way. Generating fstab the way it is told in the guide produced a bad fstab for me. I haven't got to retrying to generate fstab since then yet.