This PC, which corresponds to My Computer in earlier versions of Windows, as well as Quick Access, which replaced Favorites, and Libraries, which are a special form of saved search, are all virtual folders in the Shell Namespace.
You've already discovered the limitations of Quick Access that are the subject of countless threads -- the inabilty to rename shortcuts that point to identically named folders in different locations. No one has found a workaround to that so it's best ignored.
This PC shows connected drives, devices, network locations, and the currently logged on user's folders. While you can add custom loctions to the folders section through registry manipualtion, it's far easier to add shortcuts and/or folders to the Network Locations section.
The Text Files folder shortcut & New Folder folder were cfreated in the Network Shortcuts folder. To access this folder, click in the Address bar of Explorer & type :
shell:NetHood
Another option would be to create a custom Library of all your various Media folders from your collection of drives. If Libraries isn't currnetly visible in the Navigation Pane, right-click in the pane and check Show Libraries.
If either of these options sound good, I'm happy to proivide more info if needed.
Keith