Support

Yes, of course. That was the whole point of having a Pro version of the software since 2010.

The Video Tutorials page has examples for some often used services: Amazon S3, Dropbox, OneDrive, Google Drive. You will see that it's basically the same idea no matter which service you use, just a few service-specific options are different.

The documentation tells you which services and protocols are supported:

• Amazon S3 – this also supports all S3-compatible services such as Wasabi, OwnCloud, NextCloud etc.
• BackBlaze B2
• Box.com
• CloudMe, a bridge service which allows you to upload to several dozen third party services
• DreamObjects
• Dropbox (v2 API)
• Google Drive
• Google Storage (JSON API and legacy S3 API)
• OneDrive and OneDrive for Business
• Microsoft Windows Azure BLOB Storage service
• OVH Object Storage
• OpenStack Swift object storage which allows you to upload to any third party service supporting this protocol
• RackSpace CloudFiles
• FTP
• SFTP
• SugarSync
• WebDAV which can be used with many third party services

Please remember that third party storage services usually support one or more of the FTP, SFTP, WebDAV, S3, or OpenStack Swift protocols.

I recommend Amazon S3 as the most reliable storage vendor, and Wasabi as the best value service if you are going to be storing several hundreds of gigabytes of data e.g. if you have hundreds of sites. I also want to point out that Box.com, Dropbox, OneDrive, and Google Drive are consumer-grade storage services. They are slow, they are nowhere as reliable as the business-focused storage engines, and they are really suitable for small backups and a relatively small total amount of data stored.

Please read https://www.akeeba.com/documentation/akeeba-backup-joomla/archiver-engines.html#archiver-zip under "About the ZIP file format and its compatibility with third party software".

Just to clarify, you can still extract the ZIP archives just fine by ignoring the notification that they are invalid.