I would suggest setting a static IP to your raspberry pi based on its MAC address. If you can do this through your router or whatever is your dhcp server that would be the best route.
Then redo the installation.
I found the easiest way to install omv5 onto a pi4 is to install debian first as an sdcard flashed image (or usb or whatever boot media you choose) and then run the omv install script.
With a static IP address when the ssh session times out just restart it (ssh session) after 20 seconds or so and it should be done.
I would still do the whole raspi-config steps before actuallly installing omv5.
Thank you for your reply, so how does this sound
Freash install of Raspbian os once set up then set a static IP inside Raspbian and also onmy router, instead of installing OMV via SSH i will connect up the PI to a monitor and keyoboard and then install the code you gave?