Install PHP 7.4 on EC2

My Amazon Linux 2023 EC2 instance is currently running Apache 2.4 with PHP 8.3.7.
Because the application in /var/www/html/ was written for PHP 7.4, every request now throws an HTTP 500. The code itself is fine; the issue is purely the version mismatch.

What I need from you
• Add PHP 7.4 alongside the existing PHP 8.3, making sure mysqli, curl and json are available for the 7.4 build.
• Adjust Apache so that any script served from /var/www/html/ is executed by PHP 7.4. PHP 8.3 can remain the default for everything else.
• Verify that the site loads without 500 errors once the swap is in place.

Environment & access
• Amazon Linux 2023 on an EC2 t-series instance
• Apache 2.4 already installed
• Browser-based SSH via EC2 Instance Connect (no key pair needed) with sudo rights
• Read-only access to the code base for reference

All other preparation is done: the root cause is confirmed, the MySQL API key on Google Cloud has been refreshed, and no code edits are required.

Acceptance will be:
1. php -v shows both 8.3 and 7.4 installed.
2. php -m under 7.4 lists mysqli, curl, json.
3. Hitting the site’s main endpoints returns 200/302 responses, not 500.

If this is straightforward for you, let me know roughly how long you expect the changeover and test cycle to take, and we can get started immediately.