I know there is a Property of StarterGui or PlayerGui that makes it so you don't lose your GUIs on death, anyone know what that is? (May be a method to enable it too) I glanced at the wiki, but it it sort of unorganized?
The property you're referencing is ResetPlayerGuiOnSpawn. There is wiki documentation here.
Example:
game:GetService("StarterGui").ResetPlayerGuiOnSpawn = false