woocommerce webhooks not firing
what Linux distributions are you running for prod and dev?
CentOS with SELinux enabled with not allow HTTPD scripts and modules to connect to network by default.
setsebool -P httpd_can_network_connect onIf above is not valid, please identify network problems by trying connecting to AWS RDS via SSH CLI. If you can open a connection via SSH CLI, the problem will be with your application. If you can't, it will be network problem. First thing to check in that case is AWS RDS security group. For testing you can open 3306 to public.
Let me know how it goes.