Save Meta Data to file from within Plex

On one hand I like that plex doesn’t modify the files in the library.
On the other hand, I’d like to use just one tool, no more iflix.

It is conceivable to use a tool to rewrite the metadata in a file from plex. This would make managing metadata quite a bit easier (imho)

Is there a plugin to do this?
or ability to make a plugin to do this?

Easiest way would be to use one of the 3rd party tools used for XMBC/Kodi to create nfo files and download posters and so on. The can work alongside with Plex giving you all the metadata with your files but not requesting anything from Plex.

I, for instance, use Media Companion to do just that for my movies.