customizing .less files nothing changes in style.css

Hello, I spend hours everyday for a simple customization with no success.
I have followed the instructions given
I have added in wp-config.php
define(‘WP_MEMORY_LIMIT’, ‘256’);
set_time_limit(300);

I changed style.css, less/config.less rights to 777
(in my local pc whole site is 777 and php.ini parameters are better than described above).

I made changes to .less files but no changes activated. Actually style.css had the old values.

Also some elearningwp template overwrites files braked the functionality of the learnpress (eg. nav.php). Although it was fixed with your support the template needs to be urgently updated.
It’s a real pain to try to make simple changes with no success. These issues cost me more than a week delay.
As a developer i understand how difficult and time-consuming is to correspond with all these issues, but such issues must be fixed urgently.
Thanks

https://wordpress.org/plugins/learnpress/