You can go with a single large capacity server, such as: https://www.45drives.com/products/storinator-xl60-configurations.php Or go with a cluster and a distributed file system. It's a lot less work/less complexity to go with a large single server. Performance wise, you either care most about the cost and use hard drives or you care most about speed and use some kind of solid state storage.

If I were you, I'd call a few storage vendors and see what they say. Compare feature vs cost and then decide if you want to roll your own.

MS Windows uses IP addresses for some things, last I checked.

Give it 127.0.0.1 as its default gateway or block it at your router.

You seem to have a sample size of one with Eaton. What did Eaton Technical Support have to say? The last time I called them they were very easy to work with and very helpful. If you bought a used Eaton, you probably got a bad unit.

I just power everything off except a couple of Raspberry PIs when I'm not using it. I did the math and where I live, it's about $1/watt/year for loads that are on 24/7. It's just not worth $400/year to power something that usually idle.