Looking for feedback on my Unraid backup strategy before I pull the trigger

My Unraid server is essential to my day-to-day and even my business, so I wanted to find out what you guys are using and would recommend.

I'm running a homelab on Unraid (SWAG reverse proxy, Cloudflare DNS, Tailscale for remote access) with a handful of self-hosted services: DocuSeal (+ its own Postgres), PrivateBin, chhoto-url, Nextcloud AIO, Immich, and a few others. I'm looking to finally get real offsite backup in place instead of just local snapshots, and I want a sanity check before I build it.

My total raw data is about 500GB.

My planned setup:

• Backrest (restic with a web UI) running as a container, backing up appdata + critical shares directly to Backblaze B2 (encrypted client-side, restic repo), nightly, over the container's normal network path
• Retention: 7 daily / 4 weekly / 6 monthly snapshots, letting restic's dedup handle the versioning overhead (budgeting ~1.5–2x raw size, so ~550–730GB in the B2 bucket, roughly $4–5/month)
• Once this is validated with a real test restore, retiring the two old Appdata Backup plugin schedules and reclaiming ~561GB of local array space
• I also plan to have an off-site backup or a genuine 3-2-1 setup but want to start with Backrest directly to Backblaze B2.

Is this the right direction?

Appreciate any pushback — would rather find the holes here than during an actual restore.