It sounds like these problems are related to their end-user backup solution - can't comment on that as I've never used it.
However, when referring to Backblaze, I think most people here refer to their nice (and cheap) S3-like cloud storage solution, which works perfectly with the likes of restic, rclone and friends. That's probably what you should use if you care about control.
However, when referring to Backblaze, I think most people here refer to their nice (and cheap) S3-like cloud storage solution, which works perfectly with the likes of restic, rclone and friends. That's probably what you should use if you care about control.