A modern multicore x64 with half that RAM would run any workload that cluster could do... faster (carved into a handful of containers or VMs if you needed isolation).

It's a cool project, for fun! It would be a horrible way to do any useful work though. Just the thought of wiring it all up makes me shudder...

Computers are so fast these days you can have entire VMs in the background and not even notice them. Since Win10/11 come with HyperV and WSL you don't need to buy any separate hardware to start playing with homelba/Linux stuff.