From the example above I would like to use the data which is stored in Graph Settings >> Service field. Or the data which is in General Settings >> Host.
This should certainly be possible, if I understand correctly. Here is an example on our public sandbox instance. You will need to set a template variable based on a query, and then you can add variable foo as $foo in the Panel title:
if so, that’s a community built plugin. It looks like you want to use the value chosen in that select box as a template variable. This is probably achievable with a query-based template variable.
I would make an issue or ask for help in that plugin repo. They will have the expertise to get you unblocked here