If it’s not present, you can just add it yourself. See [HowTo] An extended guide on how to move the Plex data folder on Windows - General Discussions / Tips, Tricks & How-Tos - Plex Forum
You can also look at disabling video preview thumbnails (or at least reducing how frequently a thumbnail is generated via the GenerateBIFFrameInterval setting), as that’s most likely what’s taking the majority of the space.
