Folder apache2 missing /etc/php/8.2/apache2/php.ini

This tutorial is not for ISPConfig systems. It's not compatible. Undo all steps you did from that guide to ensure your server keeps working.

To install Joomla on an ISPConfig system, simply create a website in ISPConfig, then create a database and database user in ISPConfig. Finally, upload the Joomla source code to the web folder of that website, open the domain of that website in a browser, and follow the instructions of the Joomla installer on the screen.

 

This will likely break your setup, too, as it's a standalone software guide that reconfigures the whole web server to work for ERPnext; it is not made to be installed with other software on the same system or a hosting setup like ISPConfig. To install ERPNext, I recommend you try to install it using Docker instead and let the Docker image listen on a free port like 8090 instead of 80 or 443, then create a website in ISPConfig as a proxy vhost to provide SSL with Let's Encrypt and proxy traffic to that port.

 

Running things in docker is done to avoid such conflicts. But using a separate VM is a good option of course.