This. You should not try to backup your local cache of cloud files as if those were your local files. Use a tool that talks to the cloud storage directly.

Use tools with straightforward, predictable semantics, like rclone, or synching, or restic/Borg. (Deduplication rules, too.)

My understanding of Backblaze Computer Backup is it is not a general purpose, network accessible filesystem.[0] If you want to use another tool to backup specific files, you'd use their B2 object storage platform.[1] It has an S3 compatible API you can interact with, Computer Backup does not.

But generally speaking, I'd agree with your sentiment.

[0]: https://www.backblaze.com/computer-backup/docs/supported-bac...

[1]: https://www.backblaze.com/docs/cloud-storage-about-backblaze...