You might find https://lemm.ee/post/36819921 interesting.

You might be surprised what the material and energetic footprint of dairy is.

https://wiki.debian.org/ZFS has nice docs. I would practice in nonproduction first if you’re unfamiliar with zfs.

No hardware RAID. Use zfs, if you can. Mirror the boot SSD. I would use a stripe over mirror and 4 HDDs. Two drives are not enough redundancy. Use enterprise or nearline drives, if you can. Debian is great, you can install Proxmox on top of it, but from the sound of it plain Debian would work for you.

NATO/Russia 3rd world war, still reasonably limited to just two countries, for time being.