4 cores is a bit limiting, but definitely depends on the usage. I only have 1 VM on my NUC, everything else is docker.
I thought all the core processors had VT* extensions, I was using virtualization on my first gen i7. They are very old an inefficient now though.
I can't remember exactly what its called, but something like ~~router~~ NAT loopback is what you want. I'll have a look around. But if you set it right, things should work properly. It might be a router setting.
Found it: https://community.tp-link.com/en/home/stories/detail/1726