Thank you for advising me of your concerns!

• get multiple smaller harddrives and put them into some kind of RAID / zpool with redundancy. the drives will fail.

That’d require moving all to a different hardware platform. I hope to get the risks associated with failing drives mitigated by the Proxmox backup server

• there is absolutely zero reason to have a VM per service when a container will do. There are no advantages. But VMs will take significantly more resources and be harder to right-size. There is no restore/backup advantage using VMs.

That’s good advice! It seems I need to get comfortable with automatic backups of Docker containers and data volumes

• for that reason there is also no reason to use proxmox in the first place, unless you want to learn proxmox. Truenas scale for example comes with pre-installed k3s.

Getting familiar with Proxmox is indeed one of the reasons I switched to that route. My initial plan was to replace the mini PC with the X300 and move all to docker. Then one consideration lead to another. Maybe I need to re-evaluate whether going the Proxmox route is worth the trouble.

• I would get a separate hardware firewall because it makes easier to expand the network later.

I agree that’s another reason for having a hardware firewall besides the security aspects of having one.