Backing up and restoring multiple sites efficiently

wp-cli can do all you need from the list. This is an elegant way to work with WordPress.
Furthermore, you probably need some bash scripting to automate things even further.

I would go with that.
For instance.

Backup the database and download the database backup;
wp db export it will export the database to a file.
then you will decide where to put this backup and later you can download it.