Might not fit into your plans but if you run Proxmox you can easily backup to an offsite computer (or VM) running Proxmox Backup Server (PBS).

From their website:

By supporting incremental, fully deduplicated backups, Proxmox Backup Server significantly reduces network load and saves valuable storage space. With strong encryption and methods of ensuring data integrity, you can feel safe when backing up data, even to targets which are not fully trusted.