If you have a Workspace created you can upload folders directly to the Space.
To do this navigate to the desired Space.
Next, drag and drop your selected folder into the empty area of the Space.
You can use this method of upload if you would like to retain the folder structure.
Subfolder navigation & search:
If the folder you've uploaded contains subfolders, you can search through the subfolders by simply clicking on the desired subfolder or you can right-click and select "Search within".
You can navigate through the UI to search for the desired folder or subfolder.
Currently, the feature to directly search for folder and subfolder names using the search bar is not available.