Login to your web host control panel and switch/upgrade your PHP version to at least 7.0.
PHP 7 is 100% faster than PHP 5.6 – twice as fast and much more secure.
PHP 8 is 18.4% faster than PHP 7.4.
PHP 8.1 is 3% faster than PHP 8.
PHP 8.1 is 33% faster than PHP 7.1.