Glad you got it working.
In other news, the minimal (similarly to the standard) template now also instantiates nixpkgs i.e. you can set allowUnfree in the flake: https://github.com/Misterio77/nix-starter-configs/blob/2e4b816bd6702621417c6a2ede9be3a4d019e0aa/minimal/flake.nix#L31