Moodle doesn't have an 'installer' ... by chance are you using some app provided by hostng to install moodle? Softaculous or Direct Admin or whatever?
I asked for the output from Terminal the following command:
uname -an
If you feel uncomfortable posting here, you have my PM.
That command will give us a hint as to which linux distro your server is using ... Ubuntu/Debian/AlmaLinux/Rocky ... hopefully not almalinux 8!
Also ... appears your site doesn't know how to handle index.php files as index files for web services. Default for apache without php installed is index.html on most linux systems.
As a test, at the document root of your server, create an index.html file using your panels file browser and put nothing more than:
It Works!
in that file ... no html ... just the txt as shown above.
Then, using your browser, go to https://yoursite/ ... does the 'It Works!' show?
After that test, erase the index.html file.
So one more test from Terminal ... while this will show info about php-cli, if that is installed, the web based PHP should also be installed.
Commands:
which php
/path/seen/in/which/command/php -v
The first shows a path that we will assume is for php-cli
The /path/seen/blah/php -v
will show us version of php.
Since the moodle you are attempting to install has specific PHP requirements we need to see/know that!
'SoS', Ken