Is your feature request related to a problem? Please describe.
A clear and concise description of what the problem is. Why do you want this feature

Would be nice to have the option to store the map json files externally

Describe the solution you'd like
A clear and concise description of what you want to happen.

A configuration setting to point to a UNC path of where the map files are stored.

I know there is an option to run the web server externally, but I believe all the files are run locally on the minecraft server, and you lose some features when doing this.

Feature is already there.

Please follow the wiki at https://bluemap.bluecolored.de/wiki/getting-started/Configuration.html#webserver-configuration-webserverconf

You state the external webroot for Bluemap to dump it's worldrender.
You do so in both the webserver.conf and render.conf

I have not tested it, but you should be able to use UNC-paths as your webroot as well :)

@DatsiK96 Closing this, since i believe UNC-paths should work already.
Please reopen this if they don't work for you. Including a description on how to reproduce that issue :)