I backup my ESXi VMs and NAS file shares to local server storage using an encrypted Veeam job and have a copy job to a local NAS with iSCSI storage presented.
From there I have another host VM accessing that same iSCSI share uploading the encrypted backup to Backblaze. Unlimited "local" storage for $70\y? Yes please! (iSCSI appears local to Backblaze. They know and have already started they don't care.)
I'm backing up about 4TB to them currently using this method.
Mine is kind of similar. Hyper-V backed up with Veeam to a separate logical disk (same RAID array, different HDD's). Veeam backups are replicated to iDrive with rsync.
I need to readjust my replication schedule to prioritize the critical backups because my upload speed isn't fast enough to do a full replication that often.