Remove Apache mode_php

Per discussions on https://www.virtualmin.com/node/52367:

Note also that switching to nginx alone is unlikely to significantly alter the performance or load capacity of your system. Your application plays a much larger role in how much load the system can handle.

Using mod_fcgid or php-fpm execution modes can help. Making sure you don't have any extraneous Apache modules loaded (mod_php in particular should be disabled, if you're using fcgid or php-fpm, since it is quite large) can help. Tuning your database configuration appropriately for the load and size of your system can help.

Merely switching web servers will likely cause a very small difference. It can help with memory usage on memory-bound systems, but performance isn't really going to be fixed by running it under nginx if your app is too slow under Apache

and https://www.virtualmin.com/node/46837 comment out all entries in /etc/httpd/conf.modules.d/10-php.conf and restart Apache. It will give some errors mentioned on https://www.virtualmin.com/node/46837, so keep fixing httpd.conf until it restarts cleanly.