Too many LDAP requests, blocked by firewall

Nextcloud version: 25.0.2
Operating system and version: Linux 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64
Apache or nginx version: Apache ??
PHP version: 8.1.13

The issue you are facing:
I have setup LDAP integration using “LDAP user and group backend” which works basically (and it worked a while). Now, when synchronizing 500+ files (from personal folder, a shared folder or a group folder using desktop app), many LDAP requests are sent out and the firewall of the LDAP server blocks after a while. I have little to now influence on the firewall so I need to cut down the number of LDAP requests. How can I enable (more) LDAP caching? Is there any other way to reduce the number of accesses?
We have about 250+ users and 30 groups. In my test, only I am accessing this nextcloud installation, so these accesses come from one user alone.

Steps to replicate it:
The output of your Nextcloud log in Admin > Logging: Have not found any meaningful entry…

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!): If it could help I post it here…

The output of your Apache/nginx/system log in /var/log/____: