Proxmox is a fantastic Lab-Tool. Firing up a VM or any Linux just for a test. Especially using LXC and Templates, it’s soooo incredibly fast!
My Home Proxmox - and my LAB Proxmox are identical, but older (9 years old) HP Proliants ML110 G6 with each 16 GB RAM (maxed out). But both still serve their purpose. Newer hardware planned for end of year… 
I’m using OPNsense as firewall ( A PCengines hardware), but also as VM in Proxmox for Testing. OPNsense comes with WireGuard, just as an info…
https://www.pcengines.ch/newshop.php?c=4
I’m using the apu4d4 (Quad core CPU, 4 GB RAM, 4 Intel NICs), with a 120 GB mSSD, for about 155$ all together.
Low power, no moving parts (noise), and the big advantage is I have Internet when I’m reinstalling my Proxmox (or whatever)!
My 2 cents
Andy
A virtual LAN (vLAN99) passes Internet from a different subnet to my LAB OPNsense Firewall…