Unfortunately, I have no experience with this 
but I have to manage it somehow!
No one does until they do 
https://wiki.archlinux.org/title/Pacman/Pacnew_and_Pacsave#.pacnew
Unfortunately I could not log in via tty! Ctrl+Alt+F3 is the right shortcut for me. 
I just checked and this does have the partition; I created it when I was doing this “rebuild” of the original install cloned/copied from the old HDD. I think I was using the (then spare) EFI partition on the old disk, put there for possible future use, with the “bios_grub” flag etc…
Hope this helps to clear up any confusion!
I’ve been using Manjaro for almost 3.5 years, but unfortunately I don’t have enough knowledge to be able to follow your advice 