Unraid IS NOT RAID, but it does have the redundancy of 1 or 2 parity disks. There is no striping in Unraid.
Each data disk in the parity array is an independent filesystem, and can be read all by itself on any Linux. Each file is stored complete on a single disk, but Unraid does allow the top folders to span disks, a feature known as user shares.
Because there is no striping, Unraid read speed is limited to the speed of the single disk the file is on. Write speed in the parity array is somewhat slower than single disk speed due to realtime parity updates.
These differences from traditional RAID designs allows you to easily mix different sized disks, easily replace disks (whether due to failure or just for upsizing) and easily add disks. Each parity disk must be at least as large as any single data disk.
Unraid also has cache, which can be a multiple disk pool with various btrfs raid models supported.
You can certainly run Plex server as a docker on Unraid. To view it on the TV will require a Plex client. Lots of ways to make that happen that don't even require the server in the same room.