Restore Virtualmin from a broken OS

Hi guys, I had Webmin + Virtualmin + Mysql (and other servers) on a Ubuntu 14.04 machine.

I tried to upgrade the disto to 18.04 but, somewhere, I made some mistake. Result: the machine won't startup.

I mounted the hd with the broken OS as a secondary hd, and make a fresh install on Ubuntu 18.04 LTS.

Now I'm at loss: how can I restore Virtualmin accounts/database/and so on? I'm a dumb and I don't have a progressive backup. I have only the original HD with all the data. Any chance to recover Virtualmin, files and databases?

Thanks in advance, Cheers, Jacopo