In general your router wants dedicated physical resources in a virtualised environment as a bare minimum, passing NICS directly to the VM is the only viable option, anything else will scale badly and your router is not something you want to have waiting for CPU time. I like 'light' router builds, have played with my fair share in VM's including HA, pretty soon you realise that bare metal for a router is easier. My current box is a dual NIC Zotac i3 7100u with 16GB and a 240GB SSD, for the pittance it costs to run, it's worth keeping it bare metal, but I do/did have an HA backup that I can spin up if required.