That’s true, if there’s no load then the difference isn’t much money.
I’m running a NAS, some game servers, a forgejo instance and a jellyfin server and more on my machine so it’s never truly idle and I forgot to think about that metric.

Ah right, that rings a bell. Proxmox and Ceph sounds like a perfect experiment for OPs hardware. :)
https://pve.proxmox.com/pve-docs/chapter-pveceph.html

Yeah, I focused on the I’m just looking for some fun experiments, projects part.
I wouldn’t use the machines for anything other than experimenting for fun, they’re power hungry too if counting per performance.

I would look into setting up a proxmox cluster with high availability on them and from there you can look into fun projects that you can run as proxmox vms or lxcs.
https://www.xda-developers.com/proxmox-cluster-guide/
https://pve.proxmox.com/wiki/High_Availability

edit: HA seems to require a shared disk, such as a SAN or NAS.