hypridle seems to work just fine, so farewell swayidle

hypr/hypridle.conf

@@ -13,8 +13,8 @@ listener {
 
 listener {
     timeout = 300 # 5mins
-    on-timeout = hyprctl dispatch dpms off
-    on-resume = hyprctl dispatch dpms on
+    on-timeout = hyprctl dispatch dpms off || niri msg action power-off-monitors
+    on-resume = hyprctl dispatch dpms on || true
 }
 
 #listener {