Installation problem on Debian

Hi!
I try to make a fresh install of OC 4.0.1.1 on Debian 11.3 with PHP 8.1
But when i try to reach http://x.x.x.x/opencart/install/index.php I get the following:
<?php
ini_set('display_errors', 1);

error_reporting(E_ALL);

// Check if SSL
if ((isset($_SERVER['HTTPS']) && (($_SERVER['HTTPS'] == 'on') || ($_SERVER['HTTPS'] == '1'))) || $_SERVER['SERVER_PORT'] == 443) {
$protocol = 'https://';
} elseif (!empty($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https' || !empty($_SERVER['HTTP_X_FORWARDED_SSL']) && $_SERVER['HTTP_X_FORWARDED_SSL'] == 'on') {
$protocol = 'https://';
} else {
$protocol = 'http://';
}

// APPLICATION
define('APPLICATION', 'Install');

// HTTP
define('HTTP_SERVER', $protocol . $_SERVER['HTTP_HOST'] . rtrim(dirname($_SERVER['SCRIPT_NAME']), '/.\\') . '/');
define('HTTP_OPENCART', $protocol . $_SERVER['HTTP_HOST'] . rtrim(rtrim(dirname($_SERVER['SCRIPT_NAME']), 'install'), '/.\\') . '/');

// DIR
define('DIR_OPENCART', str_replace('\\', '/', realpath(dirname(__FILE__) . '/../') . '/'));
define('DIR_APPLICATION', DIR_OPENCART . 'install/');
define('DIR_SYSTEM', DIR_OPENCART . 'system/');
define('DIR_EXTENSION', DIR_OPENCART . 'extension/');
define('DIR_IMAGE', DIR_OPENCART . 'image/');
define('DIR_STORAGE', DIR_SYSTEM . 'storage/');
define('DIR_LANGUAGE', DIR_APPLICATION . 'language/');
define('DIR_TEMPLATE', DIR_APPLICATION . 'view/template/');
define('DIR_CONFIG', DIR_SYSTEM . 'config/');
define('DIR_CACHE', DIR_SYSTEM . 'storage/cache/');
define('DIR_DOWNLOAD', DIR_SYSTEM . 'storage/download/');
define('DIR_LOGS', DIR_SYSTEM . 'storage/logs/');
define('DIR_SESSION', DIR_SYSTEM . 'storage/session/');
define('DIR_UPLOAD', DIR_SYSTEM . 'storage/upload/');

// Startup
require_once(DIR_SYSTEM . 'startup.php');

// Framework
require_once(DIR_SYSTEM . 'framework.php');

Any ideas of what goes wrong?

Best regards
R

Your PHP extension server modules are not properly configured or installed correctly on your server.

Then what am I missing?
These are the ones reported when I check PHP modules:
bcmath
calendar
Core
ctype
curl
date
dom
exif
FFI
fileinfo
filter
ftp
gd
gettext
hash
iconv
intl
json
ldap
libxml
mbstring
mcrypt
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
Phar
posix
readline
Reflection
session
shmop
SimpleXML
soap
sockets
sodium
SPL
standard
sysvmsg
sysvsem
sysvshm
tokenizer
xml
xmlreader
xmlwriter
xsl
Zend OPcache
zip
zlib

[Zend Modules]
Zend OPcache
[PHP Modules]
bcmath
calendar
Core
ctype
curl
date
dom
exif
FFI
fileinfo
filter
ftp
gd
gettext
hash
iconv
intl
json
ldap
libxml
mbstring
mcrypt
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
Phar
posix
readline
Reflection
session
shmop
SimpleXML
soap
sockets
sodium
SPL
standard
sysvmsg
sysvsem
sysvshm
tokenizer
xml
xmlreader
xmlwriter
xsl
Zend OPcache
zip
zlib

[Zend Modules]
Zend OPcache

Regards
R

This is a PHP code, which isn't processed, but displayed instead. Check your server config.