so, while you answered, I was already trying some stuff from this thread:
I ran install-grub again, followed by an update-grub and
sudo cp /boot/efi/EFI/manjaro/grubx64.efi /boot/efi/EFI/BOOT/bootx64.efi
After the reboot, instead of getting the grub error, I get a message that my luks partition can’t be mounted and I am dropped into an emergency shell. Will try again and make a picture of the exact message…