@kueckieben netcup were being pretty lovely to get set up with but the NixOS image I created using my Flakes configuration and github.com/nix-community/nixos didn't end up booting, so that's some debugging for me to do tomorrow. Thanks for the suggestion!

Edit: nevermind I completely forgot the netcup server I chose is arm64 and tried to boot an x86_64 image on it 😬