Open protected_cart.decoded.php . You should see readable PHP:

Many old dezenders only work for PHP 5.x. As the web moves toward PHP 8.x, finding tools that can handle modern Zend Guard versions is increasingly difficult. Common Use Cases for PHP Decryption

The ability to decode Zend files depends entirely on the used to encode them.

Zend Guard and ionCube served a purpose in the 2000s-2010s. Today, PHP 8.x with JIT and OPcache makes binary encoding less effective. Additionally, most modern PHP applications are open source (Laravel, Symfony) or delivered via SaaS.

In your php.ini :

Since you are handling encrypted code, security is paramount.

Example memory dumping using GDB (conceptual):