diff --git a/Plugin/Framework/App/Response/Http.php b/Plugin/Framework/App/Response/Http.php
index 10acd93..a557945 100644
--- a/Plugin/Framework/App/Response/Http.php
+++ b/Plugin/Framework/App/Response/Http.php
@@ -2,6 +2,8 @@
 
 namespace MageOS\ThemeOptimization\Plugin\Framework\App\Response;
 
+use Laminas\Http\Header\CacheControl;
+use Laminas\Http\Header\HeaderInterface;
 use Magento\Framework\App\Config\ScopeConfigInterface;
 use Magento\Framework\App\Request\Http as HttpRequest;
 use Magento\Framework\App\Response\Http as ResponseHttp;
@@ -38,7 +40,7 @@ public function beforeSetNoCacheHeaders(ResponseHttp $subject): void
         }
 
         $cacheControlHeader = $subject->getHeader('Cache-Control');
-        if (!$cacheControlHeader) {
+        if (!$cacheControlHeader instanceof HeaderInterface) {
             return;
         }
 
@@ -63,13 +65,11 @@ public function afterSetNoCacheHeaders(ResponseHttp $subject, mixed $result): mi
             return $result;
         }
 
-        $cacheControlHeader = $subject->getHeader('Cache-Control');
-        if (!$cacheControlHeader) {
-            return $result;
-        }
-
         if ($this->isRequestCacheable === true) {
-            $cacheControlHeader->removeDirective('no-store');
+            $cacheControlHeader = $subject->getHeader('Cache-Control');
+            if ($cacheControlHeader instanceof CacheControl) {
+                $cacheControlHeader->removeDirective('no-store');
+            }
         }
         $this->isRequestCacheable = false;
 
@@ -151,10 +151,12 @@ protected function isEnabled(): bool
      */
     protected function getConfig(string $configPath, int|string|null $store = null): string
     {
-        return (string)$this->scopeConfig->getValue(
+        $value = $this->scopeConfig->getValue(
             $configPath,
             ScopeInterface::SCOPE_STORE,
             $store
         );
+
+        return is_scalar($value) ? (string) $value : '';
     }
 }
diff --git a/ViewModel/SpeculationRules.php b/ViewModel/SpeculationRules.php
index ecaec46..57ab1d3 100644
--- a/ViewModel/SpeculationRules.php
+++ b/ViewModel/SpeculationRules.php
@@ -127,7 +127,9 @@ public function getSpeculationRules(): array
      */
     public function getSpeculationRulesJson(): string
     {
-        return $this->serializer->serialize($this->getSpeculationRules());
+        $json = $this->serializer->serialize($this->getSpeculationRules());
+
+        return is_string($json) ? $json : '';
     }
 
     /**
@@ -173,7 +175,7 @@ protected function getConfigValue(string $key): ?string
             ScopeInterface::SCOPE_STORE
         );
 
-        return $value === null ? null : (string)$value;
+        return is_scalar($value) ? (string)$value : null;
     }
 
     /**
diff --git a/ViewModel/ViewTransitions.php b/ViewModel/ViewTransitions.php
index ae3a3c4..8bc55d1 100644
--- a/ViewModel/ViewTransitions.php
+++ b/ViewModel/ViewTransitions.php
@@ -26,7 +26,7 @@ protected function getConfigValue(string $key): ?string
             ScopeInterface::SCOPE_STORE
         );
 
-        return $value === null ? null : (string)$value;
+        return is_scalar($value) ? (string)$value : null;
     }
 
     /**