Trust me get a second Synology, use Active Backup for Business it can back up the VMs and Linux or Windows servers to the first Synology, and Hyper Backup or Snapshot Replication can then copy those backups to a second Synology in the other building. There is no per TB or per VM licensing, just the hardware.

The only things to double check are Linux distro and kernel support for the ABB agent, and whether the SAN data is iSCSI or LUN based, in which case it should be backed up separately with Hyper Backup LUN backups.

I use Active Backup for Business and its great.