Actually, in your case, I'm not sure. It looks like everything is configured to use PHP 7.4.x by default on a fresh installation. I would not change what was installed, but since you upgraded to 20.04 from 18.04, what happens if you remove PHP 7.2.x and install / reinstall / reconfigure PHP 7.4.x? What webserver mode are you using? Be sure to install php-fpm package for your version of php. Maybe uninstall and purge all PHP 7.2 packages before installing all of the PHP 7.4 packages?