Are there any Webmin alternatives that don't consume server resources but instead install on client machine & communicate via SSH client. So effectively all the actions made on that GUI are converted to terminal commands & executed via SSH. Are there any tools like that to communicate to a remote ubuntu server ?
In searching for GUI server admin tools, I don't recall seeing anything in the realm of what you are looking for. Webmin and Nagios are the common (free) ones and they require installation on the server.
My experience with Webmin is that it is not resource-hungry, consuming very little in the way of memory or CPU cycles.