I did something similar to this here. And someone wrote up another potentially related trick using nix-copy-closure here.
You could fairly easily build everything into the PXE image potentially like I’m doing . But nix-copy-closure might more easily let you copy whatever you want locally also. Any other deployment strategies would be relevant too here (e.g. deploy-rs or nixos-anywhere). Once you’re into a PXE image you control fully obviously, you can do pretty much whatever obviously.