Modern versions of macOS use the APFS file system. You can duplicate the entire folder structure and it won't take any additional space.
Then, open a new Finder window for the new folder. Or maybe create a new folder and move your copied folder into it. Open that folder. The trick is that you want only a single folder in a Finder window.
Change the Finder window view style to list.
Hold down the option key and click on the disclosure triangle next to your new folder.
This will expand the folder and all of the subfolders it contains.
Select all.
Go through the list. For each subfolder, hold down the command key and click it to deselect.
Once you have all of the subfolders deselected, drag them to the trash.
You're done.