Unless the fact that what stored in /www/backup/site are just the websites's data and you have to declare them to do the webserver use these trees (so, redeclare them in websites tab and regenerate associated SSL certificates), as I see it, website backups are just zip files. So, you can do what you want with these archives; including moving it to another disk or an external storage, and expand it where you want in another machine.
However, just to share my own experience: I already successfully backed up my entire server with aaPanel to an external storage relying on Restic (a stable backup tool working incrementally) through SFTP, then restored it (still through SFTP) in a VirtualBox virtual machine with the same OS (i.e. AlmaLinux) to quickly build a staging server from a prod one.
This to say that a 110 GB zip is big and heavy, so to manage this kind of volume I would rather rely on a reliable process like Restic is (and others, but Restic is the one I selected for my own use case)... But as said at top, yes, a zip file is nothing else than an archive you can move where you want.
