I do not know where you got that info from? Did you interrogate the server? I have only done an automatic install following the virtualmin guides (and your videos) so if it has set mod_php it is not something I have done deliberately. I thought I had set FGGid.
However, things have moved on a lot since I first posted and in fact I closed the post but as I am still getting responses I will continue with it.
I have rebuilt the server twice from scratch now as I could not get it to work. First time was a vanilla of Debian 10 with webmin installed over the top. Could not get ssl certificates to work. So eventually started again and am having a bit more luck this time. I am using the OVH template to install a Debian 8 server running virtualmin. Again, problems with certificates but suddenly it installed the base names of xorex.rocks and www.xorex.rocks but it will not let me add mail. or webmail. or others. However, I have assumed (maybe incorrectly) that copying the certificate to the various modules (dovecot, postfix, ftp etc.) does the same thing.
Usermin did not work but that was a closed port and is now working properly. I am now trying to resolve postfix and dovecot as they installed in a bit of a mess. For some reason hostname was based on ovh.net and in dovecot, the certificates were based on a different virtual server to the one I have set as the main server. I have edited the config files and checked the config and it now looks right (but I may have introduced a new error unwittingly). I can now send mail successfully from usermin but the mail server is not receiving replies. Also, I cannot connect to the mail account using my AppleMail client which tells me the certificate is invalid.
Until I get each piece working I am not moving on. If you can help I would appreciate it. let me know what information you need and I will post it. I am trying hard to sort things on my own but I am far from expert and have to rely on people that have responded to help me get this working.