You definitely should try something with an actual desktop. It sounds like you’re wanting a headed server with virtualization capabilities. I’d personally run LXD or KVM and LXC if I needed a type 2 hypervisor and containers like what you’re saying. Luckily, a ton of distros support both of these at this point.

Btw, proxmox utilizes KVM and LXC on the backend. So the only difference is that you’re leveraging the tools directly. If you’re a CS student then learning the underlying tools is the best way to learn about a system and how it all interacts.

It looks like Quad9 supports DoH: quad9

After looking through it a little bit, it sounds like HIP is mainly used for verifying hosts’ identities. It sounds like you’ll still need firewall rules in order to create the scenario in your example, right?