Webmin VS PowerDNS-Admin

I've tried upgrading webmin to the latest using the .sh script `/usr/share/webmin/update-from-repo.sh` and, although nuclear, didn't work!

webmin website can only be accessed on IPv4 only systems but when I tried accessing the website from an IPv6 only system, I got hostname not found. When I did a ping on www.webmin.com, I discovered it has an IPv4 address and no IPv6 address.

Maybe you are looking for this https://www.webmin.com ?

Yes. One VM to house the media (Ubuntu 20.04 LTS Server, with Samba) and one VM to run Jellyfin (also Ubuntu 20.04 LTS Server, with Jellyfin and Caddy). I have Webmin installed on both for easier oversight.

There is already Cockpit mentioned, I use from years Webmin on all my VM's

If you aren't in this to learn a lot, you may want to also consider a web hosting control panel like cPanel (not free), DirectAdmin(not free), webmin + virtualmin (free for multiple sites, virtualmin Pro is not free), Centos webpanel (not FOSS but free for non-Pro), Hestia control panel (FOSS), Plesk Obsidian (not free).

install joomla CMS to your web folder (public_html). And go to browser enter your domain and you will see setup joomla instructions. After all your web site is ready. Then you can customize your web site as you can do. Finally many thanks to developers who work for for Joomla , Virtualmin, Debian, Webmin, Let's Encrypt and more Open Source's organizations. I think people must support such Open Source's organizations My motto is that "World can be better with knowledge". ** I i wish to prepare Youtube serial for more details from start to end **

I must admit, I had to google that. I've never heard of webmin.

What you need then isn't a RMM, it is most likely a server accessible via a web interface. If you want to go the Ubuntu server rout, try out Webmin, I used it for a bit and if work well, but it's not the best.