As I said above, “It is usually in the php or phpVERSION-php package.”
If you followed any docs you found on the web, other than ours, for installing newer PHP versions or setting up PHP or whatever, they probably recommended you install that package, which is always a mistake (not just for Virtualmin, mod_php is never recommended by anyone who knows…including the PHP developers).
You can list installed php packages with dpkg -l |grep php
You’re looking for a package named simple php or a package named phpSOMEVERSION-php.