NextCloud talk extremly slow

Hi

We do have the problem, that NextCloud Talk is getting very slow recently (more than 10 seconds to load a chat).

I checked all the posts, the server tuning page and tried what I can, but I can’t find the issue for it.
Can someone help me here please?

Nextcloud version: 24.0.9
Operating system and version: 22.04
Apache or nginx version: nginx 1.18.0
PHP version: 8.0.27 (opcache enabled)
Redis: 6.0.16
CPU: 16 Cores
Memory: 26GB
Users: around 30

CPU Load is around 5% without any noticeable peaks and memory also is only around 50% used. So, hardware probably will not be the limitation here.

I checked the server tuning page and php and mysql settings are looking okay. Does someone have an idea what I could have missed or where the problem could be?

NC config

<?php
$CONFIG = array (
  'htaccess.RewriteBase' => '/',
  'instanceid' => 'XYZ',
  'passwordsalt' => 'XYZ',
  'secret' => 'XYZ',
  'trusted_domains' => 
  array (
    0 => 'XYZ',
    1 => 'XYZ',
    2 => 'XYZ',
  ),
  'datadirectory' => '/var/www/data',
  'dbtype' => 'mysql',
  'overwrite.cli.url' => 'https://XYZ.ch',
  'dbname' => 'XYZ',
  'dbhost' => 'localhost',
  'dbport' => '3306',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'version' => '24.0.9.2',
  'dbuser' => 'XYZ',
  'dbpassword' => 'XYZ',
  'installed' => true,
  'mail_smtpmode' => 'smtp',
  'mail_smtpsecure' => 'ssl',
  'mail_sendmailmode' => 'smtp',
  'mail_smtpauthtype' => 'LOGIN',
  'mail_smtpauth' => 1,
  'mail_smtphost' => 'XYZ',
  'mail_smtpport' => '465',
  'mail_from_address' => 'info',
  'mail_domain' => 'XYZ',
  'mail_smtpname' => 'XYZ',
  'mail_smtppassword' => 'XYZ',
  'overwriteprotocol' => 'https',
  'onlyoffice' => 
  array (
    'verify_peer_off' => true,
  ),
  'allow_local_remote_servers' => true,
  'force_language' => 'de',
  'force_locale' => 'de_CH',
  'skeletondirectory' => '/var/www/data/Robin/files/Anleitungen/NextCloud',
  'maintenance' => false,
  'logfile' => '/var/log/nextcloud/nextcloud.log',
  'loglevel' => 0,
  'app_install_overwrite' => 
  array (
    0 => 'announcementcenter',
    1 => 'quicknotes',
    2 => 'spreed',
    3 => 'group_everyone',
  ),
  'theme' => '',
  'apps_paths' => 
  array (
    0 => 
    array (
      'path' => '/var/www/nextcloud/apps',
      'url' => '/apps',
      'writable' => false,
    ),
    1 => 
    array (
      'path' => '/var/www/nextcloud/custom_apps',
      'url' => '/custom_apps',
      'writable' => true,
    ),
  ),
  'default_phone_region' => 'DE',
  'redis' => 
  array (
    'host' => 'localhost',
    'port' => 6379,
    'timeout' => 0.0,
    'password' => 'XYZ',
  ),
  'activity_expire_days' => 60,
  'filelocking.enabled' => true,
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'memcache.local' => '\\OC\\Memcache\\Redis',
  'integrity.excluded.files' => 
  array (
    0 => '.htaccess',
  ),
  'updater.secret' => 'XYZ',
);