I don’t know if it’s a smart solution but I have a HDD in my server that is used just for backups, each night I have rsync automatically moving stuff from multiple locations that I want to back up onto the drive. After that is done I have Kopia backup to B2, with compression, deduplication and encryption. I use healthchecks.io as well to alert me if any of the steps fails to complete (but none of the steps block each other).