, you wrote:
1. how do I make a file copy
of the entire disk
2. All Synology tools (in particular Hyper Backup) seem quite daft about this
3. giving the impression that I can only do per-folder backups
4. OF COURSE I would like to specify multiple source folders
5. I also find that using USB Copy, I cannot create more than one backup task targeting the same USB drive?
6. setting up a complete file copy to a USB disk
7. I just want to create one deep offline copy of everything, in a readable format (files)
8. Is it a mistake to have more than one shared folder on a Synology NAS?
So, let's clean up your own mess first to understanding scope.
A. What is the purpose = file copy
of the entire disk?:
i) data backup = to be ready restore your last backup when your disk (in NAS) will pass away
ii) data transport to different location or to portable media (USB stick)
B. Do you need one time entire disk copy from NAS into USB attached disk? Y/N
I don't know, what NAS do you have. However, please take into consideration, that you can't copy DSM system files, but you can backup installed packages (include their setup).
C. Did you mean = the disk copy
= is copy of your Shared folder/s operated in your NAS? Y/N
D. Did you mean = multiple source folders = Shared folders or particular folder in Shared folder tree?
E. Did you read carefully Synology KB
for - How to back up your data to USB with Hyper Backup.
What isn't clear?
F. Did you mean = setting up a complete file copy to a USB disk = is mistakenly used "file" instead "entire folders"? Y/N
G. All files used for Copy or Backup (Hyper Backup) you can find in readable format and you can Copy/Restore precise folder/s or file/s back to NAS. It is general feature.
It is not a mistake to have more than one shared folder on a Synology NAS. It is useful feature.
Using Synology is time-consuming for newcomers... the simplest things are not...
.... Yes it can be frustrating, when you can't read tutorials and use a hooray action, w/o preparation. But as you see we can help you.