I've used VirtualminPro to run a Centos server for the past 12 years and have backed up to the Amazon S3 servers using Virtualmin's scheduled backup ever since Virtualmin developers made it available.
Would it be possible to add in support for BackBlaze B2 Cloud Storage ? https://www.backblaze.com/b2/cloud-storage.html
It is bucket oriented but is less expensive than S3.
I've known about BackBlaze but investigated it last night when I discovered it was built into Akeeba Backup. It worked very well and thought it would be a nice, less expensive Amazon alternative to ask for in the BlueSkies forum.