I am not clear, what the current state is and what route you would like to take.
Do you have a fresh installation of OMV 5 running on a new boot disk?
So the next step is to connect the old boot drive in addition to the new one, mount it to /mnt and copy the contents of the directory /mnt/var/lib/docker to /var/lib/docker and /mnt/etc/docker/* to /etc/docker.
This will give you back your docker stuff.
Now disconnect the boot drive and connect the data drives and reconfigure OMV.