I don’t think this has anything to do with home manager. The error message states that an expected attribute is missing. In this case, it is the type type.attrTag.
The type lib.type.attrTag was added only recently. The problem is that the Kanshi service is using this tag already and thus only works with the unstable branch.
error: attribute 'attrTag' missing
at /nix/store/0b11p5g24mgl5qfg34khvjs3fh91vdx4-source/modules/services/kanshi.nix:9:19:
8|
9| directivesTag = types.attrTag {
| ^
10| profile = mkOption {
Try switching to unstable nixpkgs. In your flake file change nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11"; to nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";