Virtualization mostly. I need Win 10 and Kali Linux to run at the same time on the host distro.
For just two VM, any Linux distro is enough, virt-manager
to easily run those VMs up and done. The default network will allow them to communicate between their NAT. Proxmox sounds too many complications for just some testing or development stuff.
Proxmox is a lot more user friendly than virt-manager (yes I’ve used both, but I just started using proxmox).