Hi,
I've tried Backup for Mac 2.10.2.73 in order for make a cloud copy of time machine in Azure Blob archive tier storage.
From the very beginning MSP360 looked very promising for this task but finally I've got rid of it and that's why.
I experimented with encrypted time machine backup of 310GB and of ~40k files.

Uploading to Azure:
- consistent speed is 60Mbps, write operations mainly consist from PutBlob and SetBlobTier, archive tier set correctly, directly to Archive Tier. In total about 80k write operations.
Restoration from Azure:
- correct rehydration process, directly from archive tier to hot tier, the process of rehydration of 40k blobs took about 58 hours cause it was about 80k GetBlobProperties and SetBlobTier operations. Consistent download speed from Azure about 130Mbps but the process stuck at 40GB point and has never finished.

Summary: to get advantage of cheap azure archive tier storage and save money it would be better to write time machine backup by one single blob with PutBlock operations. By this way we can save money by decreasing the SetBlobTier operation quantity, save time on rehydration process and provide with stability of a recover process.

It would be great to get feedback from developers, what they think about. One day may be we can finally effectively use azure just for $1 for 1TB of cloud storage.

Cheers.