Got a “Dell Wyze 5070 extended”, the extended is important because it lets it have a half height PCIe card. Put a dual NIC Intel card in it. It came with 8 GB of RAM and a 64 GB SATA M.2 drive, plenty. Price out a power brick if it doesn’t come with one, which is a Dell laptop one; it refuses to turn on with a PCIe card in and if the power brick is less than 130W (DA130PE1-00 is a product # of it)!! Very annoying. Note the Intel atom processor in it lacks AVX2 instructions which makes mongoDB past v4 not work on it, so you can’t run the Unifi controller, which has vexed me. But it’s fine for internet routing! Never tested throughput but others have online.

(Note: I would not do this now!) I put proxmox on it then did opnsense (passing through the PCIe NICs) and Debian. I chose opnsense over openwrt because opnsense had an automatic update functionality, while openwrt required you to manually wipe the OS and reinstall - when they fix nasty upgrade path that I’ll come knockin. (Openwrt is like that because that’s how routers do upgrades)

I would not choose proxmox now because its upgrade path is fraught since the free level is rolling and they’ve had critical breaking update errors in the past. No good for your router setup. I want upgrades on and automatic so I don’t get kiddie script hacked.

I’m prepping to do either opnsense only and not in a VM or Debian with Incus (VM manager like promox, but not its own OS) installed and then opnsense in a VM. I’m leaning opnsense direct to just make sure my router works, but I’ve never had trouble with Debian yet so still pondering.

I run a pihole and wireguard on the current Debian VM, and opnsense can do wireguard so most of the way there. In the future I’ll switch that pihole instance (wherever it is) to adguardhome, the local rewrite rules in pihole don’t support wildcards so it’s annoying af to have to load in every local domain I set up.

This has worked well for years and I’ve never measured power but I presume it is low.

Hope this infodump helps!