(In case this isn't changed to the official AWS blog link)

"There are two other patches that impact the performance of the WordPress-NGINX benchmark, and both have been applied to master and PHP-7.4 branch:"

A patch to disable the use of huge pages in memory allocator fixed a 10% performance regression: https://github.com/php/php-src/commit/928c42211f737640e4dc3c...

The patch to enable the Zend Optimizer on ARM64 accounts for about 5% of better performance on M6g instances https://github.com/php/php-src/commit/4d7df449d0ab389b01b45f...