If you can reinstall:
- use manual partitioning
- set the EFI partition to mount to
/boot/efi
(if relevant) - set your m2 to mount to
/
- set your hdd to mount to
/home
- set the EFI partition to mount to
If you don’t want to reinstall:
- copy everything from
/home
to your hard drive - edit
/etc/fstab
to mount your drive to/home
: [root tip] Mount partition using fstab - reboot
- confirm your drive is currently mounted to
/home
- confirm your system works well
- boot into a LiveUSB
- delete the content of
/home
from your m2
Also, i spot that you encrypted your root partition, but your hdd is not. If you want to encrypt your data, you should change its partitioning beforehand.