made it work

hosts/default/configuration.nix

@@ -37,7 +37,10 @@
 
   # Enable the X11 windowing system.
   services.xserver.enable = true;
-  services.xserver.displayManager.sddm.enable = true;
+  services.xserver.displayManager = {
+    sddm.enable = true;
+    sessionPackages = [ pkgs.hyprland ];
+  };
   services.xserver.windowManager.i3.enable = true;
 
   # services.xserver.xkb.options = "eurosign:e,caps:escape";

hosts/default/hyprland.conf

@@ -6,6 +6,7 @@ monitor=,preferred,auto,1,mirror, eDP-1  # default treatment for external monito
 #monitor=,preferred,auto,1 # default treatment for external monitors
 
 # Environment variables
+env = WLR_RENDERER_ALLOW_SOFTWARE,1 # fix for running in VM
 env = XCURSOR_SIZE,24
 env = XCURSOR_THEME,Breeze
 env = XDG_CURRENT_DESKTOP,Hyprland
@@ -50,7 +51,7 @@ exec-once = fcitx5 -d
 exec-once = dunst
 exec-once = /usr/lib/kdeconnectd
 
-set $gnome-schema org.gnome.desktop.interface
+# set $gnome-schema org.gnome.desktop.interface
 exec-once = gsettings set $gnome-schema gtk-theme 'Arc Dark'
 exec-once = gsettings set $gnome-schema icon-theme 'Arc Dark'