made some progress

modules/nixos/boot/default.nix

@@ -0,0 +1,81 @@
+{ lib, namespace, config, ... }:
+let
+  inherit (lib) mkIf mkMerge mkDefault mkEnableOption;
+  inherit (lib.types) enum;
+
+  cfg = config.${namespace}.boot;
+in
+{
+  config.${namespace}.boot = {
+    type = mkOption {
+      type = enum [ "bios" "uefi" ];
+      default = "uefi";
+    };
+
+    quiet = mkOption {
+      type = bool;
+      default = false;
+    };
+
+    animated = mkOption {
+      type = bool;
+      default = false;
+    };
+  };
+
+  config = mkMerge [
+    ({
+      boot.loader.grub.enable = mkDefault true;
+    })
+
+    (mkIf cfg.type == "bios" {
+      boot.loader.grub.efiSupport = false;
+    })
+
+    (mkIf cfg.type == "uefi" {
+      boot.loader = {
+        efi.canTouchEfiVariables = true;
+        grub = {
+          efiSupport = true;
+          efiInstallAsRemovable = mkDefault false;
+          device = "nodev"; # INFO: https://discourse.nixos.org/t/question-about-grub-and-nodev
+        };
+      };
+    })
+
+    (mkIf cfg.quiet {
+      boot = {
+        consoleLogLevel = 0;
+
+        initrd = {
+          systemd.enable = true;
+          verbose = false;
+        };
+
+        kernelParams = [ 
+          "quiet"
+          "loglevel=3"
+          "systemd.show_status=auto"
+          "udev.log_level=3"
+          "rd.udev.log_level=3"
+          "vt.global_cursor_default=0"
+        ];
+
+        loader.timeout = mkDefault 0;
+      };
+    })
+
+    (mkIf cfg.animated {
+      boot.plymouth = {
+        enable = true;
+        
+        theme = mkDefault "pixels";
+        themePackages = with pkgs; [
+          (adi1090x-plymouth-themes.override {
+            selected_themes = [ "pixels" ];
+          })
+        ];
+      };
+    })
+  ];
+}