You're welcome.
When you login to a remote box using OpenSSH, files are not being shared. OpenSSH doesn't even have a graphical interface. But you can forward other interfaces like we saw at the meeting where we forwarded the xfce4 desktop to show up on the local machine. It's like we projected the desktop environment from the remote box to the local box.
Although OpenSSH, OMV and NC might be able to do some similar things, comparing OpenSSH to those two is like comparing apples and oranges.
OpenSSH isn't meant for sharing files. It's meant for no holds barred full access. Once you're logged in, you could delete every single file on the remote box. You could write shell scripts, you can install, update or remove packages. You don't just "see" the files on the remote machine with OpenSSH, you're logged into the remote machine and have all the same powers as if you were logged into it locally.
OMV and NC are meant for being repositories of files, usually documents or media files. OpenSSH can only share files via SFTP (Secure FTP) but it does so so much more than that.
OpenSSH is remote access software that let's you do anything you want to the server, OMV and NextCloud are essentially file servers. That's a huge difference.
For example, when I ssh to the PLUG server that runs this SMF-based forum, and the front pages of the site (Drupal-based), I have full power. You can't configure the PLUG webserver using OMV or NC. They would be primarily used to have a group-shared directory of media files accessible over the internet via a web browser (assuming OMV does, I'm pretty sure that NextCloud does).
There's no comparison between file/media servers and a remotely accessed shell. It's not a case of comparing which has better features because they do very different things.
OpenSSH is about controlling remote boxes entirely.
OMV and NC are about sharing files on a remote server using a web browser.
They can work in concern or separately. For example, you could use ssh to login to an remote box with OMV on it and turn OMV off or even shut down or restart the machine.
Because OpenSSH connects you to a terminal so you can do anything you normally can do in a terminal. With OMV or NC you're limited to what the interface is written to allow you to do and it's limited compared to what the terminal offers. Openssh essentially gives you full terminal access.
If you were to compare other software to OpenSSH, then you'd choose, for example, VNC or RDP which are other ways of getting remote access to a box.
Hopefully, that's more clear.
