So, I've followed along with a arm vps. I have lemmy setup, but I'm missing the part on how to federate it. I went into the admin console and added sites to the "allowed instances" hit save, but I refresh the page and they are gone. What am I missing here?

Yes. Under the hood, it just uses "rclone crypt" functionality. It's a little hard to find, it's all the way down on the Cloud Sync Task setup but it's there.

Yup, both NASs are running TrueNas Scale, which have a setting for Encryption on Cloud Sync Tasks. (Encrypts both filename and file contents)

Main NAS backups to Secondary NAS (onsite - 10G link). Secondary NAS backups up to Offsite (Hetzner server) weekly. Only important data, not Linux ISOs etc.