All the data is highly compressed and binary. I would just save it off as it is, Time Machine or any other file copy is sufficient and efficient in storage to back up your Photos library data within the library.
It is a package which is a fancy name for a structured folder on disk, so that’s why it’s easy to copy off using a variety of tools.
Here's a different approach:
In essence, type the following commands in Terminal.app:
Reveal the file path of the current wallpaper on the Desktop:
defaults write com.apple.dock desktop-picture-show-debug-text -bool TRUE; killall Dock
Once revealed, hide the file path ...
You can make albums, share links and make the albums public on macOS.
Create a "New Shared Album" and turn on "Public Website" in People's tab in the album itself, not the global one.
You can even share albums with friends and family who don't use iCloud. Just open a Shared Album that you created, go to the People tab on your iOS device or ...
Everything is named per the database and systems, so please resist the urge to move anything.
You can secure that data with an encrypted disk image if needed or encrypt the whole drive transparently with the current FileVault scheme if that’s what’s the main concern.
Unless you want to export out the files to disk, I wouldn’t touch it.
The best tool ...