Fire also creates activity.

An old laptop from about 13 years ago barely breaks a sweat running proxmox and a handful of containers and two vms.

Waste not want not. Plus it comes with a keyboard, touchpad and monitor. Plus, built in ups. You might need to add a USB Ethernet dongle but you don’t have to.

I bet just about anyone you know has their old laptop in a drawer somewhere. They’d probably give it to you.