Is anyone using modern ARM mac hardware in a home server/lab environment? I feel like a trio of new mac mini's would be the ultimate power/performance ratio cluster, assuming you could run something like Proxmox there.

not yet but they do seem to be a very capable piece of hardware for running LLMs

I do love that we are still using Doom 2016, an eight year old game, as an example of modern AAA. It is an incredible game.