From the object lists, when a CSV file is created or exported to another database, the generated file does not contain more than 1000 lines.
The problem is related to a PHP limitation. To bypass it, you must increase a parameter in a configuration file.
Edit the file /etc/php/7.2/apache2/php.ini
Look for the variable max_input_vars. Delete the semicolon at the beginning of the line, and increase the value to 10000.
systemctl restart apache2