If the zpa is not loaded in phpinfo it is possible that the agent is not registered properly or the apache/fpm service is not restarted.
Kindly ensure if
1. zpa.ini is present in the respective ini directory. You can find this using the following command
php -i | grep "Scan this dir for additional .ini files"
2. zpa.so copied is the corresponding API version. In your case, ensure you have copied "/opt/zpa/lib/zpa20170718.so" to "/opt/cpanel/ea-php72/root/usr/lib64/php/modules/zpa.so" . Note that the file name must be zpa.so in the destination directory (obtained from php -i|grep extension_dir).
3. Restart the apache/php-fpm service. And verify again using "php -i | grep zpa"
Kindly let us know if this works.
Thanks & Regards,
Developer, APM Insight PHP Agent