The little mini-pc I'm using to test Proxmox unfortunately only has a single 1gb ethernet port. Since most of my network is 10 gig, I decided to see if I could at least get 2.5 gig working, since this box doesn't have thunderbolt and those adapters are super pricey anyways.
I picked up this Anker adapter from Amazon: Anker USB C to 2.5 Gbps Ethernet Adapter
All I had to do was plug it in and create a bridge with it within Proxmox. I assigned an adapter to my Windows host (using the VirtIO Paravirtualized driver) and installed the driver from the Qemu guest agent ISO: https://pve.proxmox.com/wiki/Qemu-guest-agent
And that was that. I now have 2.5 gig ethernet for Proxmox!
