Try this onlyoffice config

nixos/queen/configuration.nix

@@ -56,6 +56,8 @@
   sops.secrets."nextcloudadmin".owner = config.users.users.nextcloud.name;
   sops.secrets."nextclouddb".mode = "0440";
   sops.secrets."nextclouddb".owner = config.users.users.nextcloud.name;
+  sops.secrets."local.json".mode = "0440";
+  sops.secrets."local.json".owner = config.users.users.onlyoffice.name;
 
   nix = {
     gc = {
@@ -146,7 +148,7 @@
       extraGroups = ["sudo" "networkmanager" "wheel" "vboxsf"];
       shell = pkgs.zsh;
     };
-    nextcloud.extraGroups = [config.users.groups.keys.name "aria2"];
+    nextcloud.extraGroups = [config.users.groups.keys.name "aria2" "onlyoffice"];
   };
 
   # Enable completion of system packages by zsh

nixos/queen/nextcloud.nix

@@ -24,6 +24,10 @@
         ## LetsEncrypt
         enableACME = true;
       };
+      "onlyoffice.example.com" = {
+        forceSSL = true;
+        enableACME = true;
+      };
     };
   };
 
@@ -41,11 +45,16 @@
     autoUpdateApps.enable = true;
     # Set what time makes sense for you
     autoUpdateApps.startAt = "05:00:00";
+    configureRedis = true;
+    maxUploadSize = "16G";
+    enableBrokenCiphersForSSE = false;
 
     config = {
       # Further forces Nextcloud to use HTTPS
       overwriteProtocol = "https";
 
+      defaultPhoneRegion = "NL";
+
       # Nextcloud PostegreSQL database configuration, recommended over using SQLite
       dbtype = "pgsql";
       dbuser = "nextcloud";
@@ -58,6 +67,12 @@
     };
   };
 
+  onlyoffice = {
+    enable = true;
+    hostname = "onlyoffice.example.com";
+    jwtSecretFile = config.sops.secrets."local.json".path;
+  };
+
   # Enable PostgreSQL
   services.postgresql = {
     enable = true;
@@ -78,7 +93,7 @@
   };
 
   systemd.services."sops-nix.service" = {
-    before = ["nextcloud-setup.service" "postgresql.service"];
+    before = ["nextcloud-setup.service" "postgresql.service" "onlyoffice.service"];
   };
 
   # Ensure that postgres is running before running the setup