@HomeGrownHeroz Kodi can't act as a Plex Media Server, they are two different things, with some similar features.
Kodi can also act as a media server, although in a different way, all devices needs to have a full Kodi installation. Plex is easier to setup, as a media server and the respective clients.
What you can do in Kodi is using it as a Plex Client, using the addon below, which will be connected to a Plex Media Server, that is what you installed in Raspbian.
https://kodi.tv/plex-add-on-for-kodi
