diff --git a/.vscode/lemmur.code-snippets b/.vscode/lemmur.code-snippets
index 815ff39..8f926b5 100644
--- a/.vscode/lemmur.code-snippets
+++ b/.vscode/lemmur.code-snippets
@@ -28,6 +28,6 @@
   },
   "L10n string": {
     "prefix": "l10n",
-    "body": ["L10n.of(context).$0"]
+    "body": ["L10n.of(context)!.$0"]
   }
 }
diff --git a/lib/l10n/l10n.dart b/lib/l10n/l10n.dart
index 3484ed9..ccf6c2a 100644
--- a/lib/l10n/l10n.dart
+++ b/lib/l10n/l10n.dart
@@ -6,8 +6,8 @@ export 'l10n_api.dart';
 export 'l10n_from_string.dart';
 
 abstract class LocaleSerde {
-  static Locale? fromJson(String? json) {
-    if (json == null) return null;
+  static Locale fromJson(String? json) {
+    if (json == null) return const Locale('en');
 
     final lang = json.split('-');
 
diff --git a/lib/stores/accounts_store.g.dart b/lib/stores/accounts_store.g.dart
index 2b909ae..c041829 100644
--- a/lib/stores/accounts_store.g.dart
+++ b/lib/stores/accounts_store.g.dart
@@ -8,20 +8,19 @@ part of 'accounts_store.dart';
 
 AccountsStore _$AccountsStoreFromJson(Map<String, dynamic> json) {
   return AccountsStore()
-    ..tokens = (json['tokens'] as Map<String, dynamic>)?.map(
+    ..tokens = (json['tokens'] as Map<String, dynamic>?)?.map(
           (k, e) => MapEntry(
               k,
-              (e as Map<String, dynamic>)?.map(
-                (k, e) =>
-                    MapEntry(k, e == null ? null : Jwt.fromJson(e as String)),
+              (e as Map<String, dynamic>).map(
+                (k, e) => MapEntry(k, Jwt.fromJson(e as String)),
               )),
         ) ??
         {'lemmy.ml': {}}
-    ..defaultAccounts = (json['defaultAccounts'] as Map<String, dynamic>)?.map(
+    ..defaultAccounts = (json['defaultAccounts'] as Map<String, dynamic>?)?.map(
           (k, e) => MapEntry(k, e as String),
         ) ??
         {}
-    ..defaultAccount = json['defaultAccount'] as String;
+    ..defaultAccount = json['defaultAccount'] as String?;
 }
 
 Map<String, dynamic> _$AccountsStoreToJson(AccountsStore instance) =>
diff --git a/lib/stores/config_store.dart b/lib/stores/config_store.dart
index f27822a..33b4a0f 100644
--- a/lib/stores/config_store.dart
+++ b/lib/stores/config_store.dart
@@ -33,11 +33,11 @@ class ConfigStore extends ChangeNotifier {
     save();
   }
 
-  Locale? _locale;
-  // default value is set in the `load` method because json_serializable does
-  // not accept non-literals as constant values
+  late Locale _locale;
+  // default value is set in the `LocaleSerde.fromJson` method because json_serializable does
+  // not accept non-literals as defaultValue
   @JsonKey(fromJson: LocaleSerde.fromJson, toJson: LocaleSerde.toJson)
-  Locale get locale => _locale ?? const Locale('en');
+  Locale get locale => _locale;
   set locale(Locale locale) {
     _locale = locale;
     notifyListeners();
diff --git a/lib/stores/config_store.g.dart b/lib/stores/config_store.g.dart
index 2268fc6..af41b4a 100644
--- a/lib/stores/config_store.g.dart
+++ b/lib/stores/config_store.g.dart
@@ -10,8 +10,8 @@ ConfigStore _$ConfigStoreFromJson(Map<String, dynamic> json) {
   return ConfigStore()
     ..theme = _$enumDecodeNullable(_$ThemeModeEnumMap, json['theme']) ??
         ThemeMode.system
-    ..amoledDarkMode = json['amoledDarkMode'] as bool ?? false
-    ..locale = LocaleSerde.fromJson(json['locale'] as String);
+    ..amoledDarkMode = json['amoledDarkMode'] as bool? ?? false
+    ..locale = LocaleSerde.fromJson(json['locale'] as String?);
 }
 
 Map<String, dynamic> _$ConfigStoreToJson(ConfigStore instance) =>
@@ -21,36 +21,41 @@ Map<String, dynamic> _$ConfigStoreToJson(ConfigStore instance) =>
       'locale': LocaleSerde.toJson(instance.locale),
     };
 
-T _$enumDecode<T>(
-  Map<T, dynamic> enumValues,
-  dynamic source, {
-  T unknownValue,
+K _$enumDecode<K, V>(
+  Map<K, V> enumValues,
+  Object? source, {
+  K? unknownValue,
 }) {
   if (source == null) {
-    throw ArgumentError('A value must be provided. Supported values: '
-        '${enumValues.values.join(', ')}');
+    throw ArgumentError(
+      'A value must be provided. Supported values: '
+      '${enumValues.values.join(', ')}',
+    );
   }
 
-  final value = enumValues.entries
-      .singleWhere((e) => e.value == source, orElse: () => null)
-      ?.key;
-
-  if (value == null && unknownValue == null) {
-    throw ArgumentError('`$source` is not one of the supported values: '
-        '${enumValues.values.join(', ')}');
-  }
-  return value ?? unknownValue;
+  return enumValues.entries.singleWhere(
+    (e) => e.value == source,
+    orElse: () {
+      if (unknownValue == null) {
+        throw ArgumentError(
+          '`$source` is not one of the supported values: '
+          '${enumValues.values.join(', ')}',
+        );
+      }
+      return MapEntry(unknownValue, enumValues.values.first);
+    },
+  ).key;
 }
 
-T _$enumDecodeNullable<T>(
-  Map<T, dynamic> enumValues,
+K? _$enumDecodeNullable<K, V>(
+  Map<K, V> enumValues,
   dynamic source, {
-  T unknownValue,
+  K? unknownValue,
 }) {
   if (source == null) {
     return null;
   }
-  return _$enumDecode<T>(enumValues, source, unknownValue: unknownValue);
+  return _$enumDecode<K, V>(enumValues, source, unknownValue: unknownValue);
 }
 
 const _$ThemeModeEnumMap = {