Limit resources for nixos-upgrade systemd service

system/default.nix

@@ -1,5 +1,6 @@
 {
   config,
+  lib,
   pkgs,
   iosevkaCustom,
   ...
@@ -52,15 +53,19 @@
       randomizedDelaySec = "15min";
       flags = [
         "--accept-flake-config"
-        "--keep-going"
-        "--max-jobs"
-        "1"
         "--option"
         "extra-binary-caches"
         "https://nix.xenia.me.uk"
       ];
     };
   };
+  systemd.services = lib.mkIf config.system.autoUpgrade.enable {
+    nixos-upgrade.serviceConfig = {
+      CPUQuota = "75%";
+      CPUWeight = 20;
+      IOWeight = 20;
+    };
+  };
   boot.loader = {
     systemd-boot.enable = true;
     efi.canTouchEfiVariables = true;