In reply to @k900:0upti.me
Is your Sway from the same nixpkgs as the rest?

I think so. This is the sway binary I use (this is configured in home-manager, same nix codebase, but completely unconnected to nixos, beyond sharing same flake inputs):

  programs.bash.profileExtra = let
    systemd-cat = "${pkgs.systemd}/bin/systemd-cat";
    sway = "${config.wayland.windowManager.sway.package}/bin/sway";
  in ''
    if [ -z $DISPLAY ] && [ "$(tty)" = "/dev/tty4" ]; then
       # https://wiki.archlinux.org/title/Sway#Automatically_on_TTY_login
       exec ${systemd-cat} --identifier=sway ${sway}
    fi
  '';

This is my sway config on the nixos side of same flake inputs-sharing nix-repo:

_:
# Sway specific stuffs (fixes that must be system based - instead of home-manager based)
{
  # Allow Wayland stuff to use OpenGL
  #  (Anything installed via Home-Manager needs a new switch for this to take effect)
  hardware.opengl.enable = true;

  # Necessary according to Nixos Wiki for Sway under HM:
  security.polkit.enable = true;

  # Allow swaylock to unlock machine;
  #   necessary due to: https://github.com/NixOS/nixpkgs/issues/143365
  programs.sway.enable = true;

  # Allow screensharing:
  services.pipewire = {
    enable = true;
    alsa.enable = true;
    pulse.enable = true;
  };

  xdg.portal = {
    enable = true;
    wlr.enable = true;
    # Don't enable unless sway.wrapperFeatures.gtk is also enabled
    # extraPortals = [pks.xdg-desktop-portal-gtk];
    # gtkUsePortal = true;
  };

  # Enable icons for say, Gnome applications
  xdg.icons.enable = true;
}

In reply to @k900:0upti.me
Do you maybe have different versions of the flake activated though

In reply to @9hp71n:matrix.org
Isn't this "${config.wayland.windowManager.sway.package} some HM thing that should not be used on NixOS ?
This one: programs.sway.enable = true; uses other package with some NixOS specific overrides inside.

Nevermind, I think it should be okay ?
https://nix-community.github.io/home-manager/options.xhtml#opt-wayland.windowManager.sway.package

Sway package to use. Will override the options ‘wrapperFeatures’, ‘extraSessionCommands’, and ‘extraOptions’. Set to null to not add any Sway package to your path. This should be done if you want to use the NixOS Sway module to install Sway.
I know NixOS module does some things inside:
https://github.com/NixOS/nixpkgs/blob/a77ab169a83a4175169d78684ddd2e54486ac651/nixos/modules/programs/wayland/sway.nix#L34
but they are probably not related your issue.

Nevermind, I think it should be okay ?
https://nix-community.github.io/home-manager/options.xhtml#opt-wayland.windowManager.sway.package

Sway package to use. Will override the options ‘wrapperFeatures’, ‘extraSessionCommands’, and ‘extraOptions’. Set to null to not add any Sway package to your path. This should be done if you want to use the NixOS Sway module to install Sway.

I know NixOS module does some things inside:
https://github.com/NixOS/nixpkgs/blob/a77ab169a83a4175169d78684ddd2e54486ac651/nixos/modules/programs/wayland/sway.nix#L34
but they are probably not related your issue.