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