server: fix weird dns problems in nextcloud by switching to systemd-networkd

hosts/kabtop/hardware-configuration.nix

@@ -114,32 +114,36 @@
     networkmanager = {
       enable = false;
     };
-    interfaces = {
-      ens18 = {
-        useDHCP = false;                     # For versatility sake, manually edit IP on nm-applet.
-        ipv4.addresses = [ {
-            address = "37.44.215.182";
-            prefixLength = 24;
-        } ];
-        ipv6.addresses = [ {
-            address = "2a13:7e80:0:ef::2";
-            prefixLength = 64;
-        } ];
-      };
-    };
-    defaultGateway = "37.44.215.1";
-    defaultGateway6 = {
-      address = "fe80::1";
-      interface = "ens18";
-    };
-
-    nameservers = [ "9.9.9.9" "2620:fe::fe" ];
     firewall = {
       enable = true;
       allowedUDPPorts = [  ];
       allowedTCPPorts = [ 80 443 ];
     };
   };
+  systemd.network = {
+      enable = true;
+      networks = {
+          "10-lan" = {
+              matchConfig.Name = "ens18";
+
+              address = [
+                "37.44.215.182/24"
+                "2a13:7e80:0:ef::2/64"
+              ];
+
+              routes = [
+                {  Gateway = "37.44.215.1"; }
+                {  Gateway = "fe80::1"; }
+              ];
+
+              dns = [
+                "9.9.9.9"
+                "2620:fe::fe"
+              ];
+          };
+      };
+  };
+
 
   hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
 }