I'm still trying to wrap my head around this convoluted sharing mission you're on. Help me out with this please.
If I'm understanding you correctly you:
Have plex installed on your current desktop?
Have freenas up and running on a separate system?
Are sharing media files from your desktop to your TV via WMP DLNA function?
Are sharing other files from your desktop with other windows machines though your shared folders?
And if I understand you correctly what you are trying to accomplish is move the files to your FreeNAS and continue to share as you have been?
Have I missed anything?
Also how is the TV connected to your network?
You're correct on all of the above, except that I don't have Plex installed as a program on the desktop. Plex is installed as a plugin on the NAS (running FreeNAS).
Plex is up and running, but the interface is slow. Furthermore the goal is to be able to just use the remote and not use things like play to etc. etc.
The LAN contains a network modem connected to the outside line (cable 180Mb) and running a 1gb line to the WAN port of the router (asus ac68u). The router functions as the gateway, (wifi)router etc. etc. 2 1Gb lines go to the switch (TP link 16 port managable switch). The NAS is connected to the switch trough a two poort NIC (LAG 2x 1Gb). Two desktops the TV etc. etc. are also connected to the switch through 1Gb lines. A couple of laptops, tablets and cel phones connect to the router via ac wifi.
All computers and the NAS (running FreeNAS) can share files and are discoverd on the network, share files and stream media. I can stream media from any workstation to the TV and the TV sees al the Wmp content. Using plex a can also stream media to the TV, but the TV doesn't find plex on the network, although it does work through the plex app that I've downloaded on the TV.
Because the TV does notice the WMP's on the network, the goal is to use the desktops as throughput for the files from the NAS.