Once the permission on WP files are tightened (see https://wordpress.org/support/article/hardening-wordpress) you might experience issues with updating the plugins and themes.
To get around this the webserver user should be the owner of the wp-content folder and its content and have write access there. This is usually the user www-data.
So run this:
chown -R user wordpress_installation
chown -R www-data wordpress_installation/wp-content
find /path/to/your/wordpress/install/ -type d -exec chmod 755 {} \;
find /path/to/your/wordpress/install/ -type f -exec chmod 644 {} \;
This user should also be the owner of the file.php located in wp-admin/includes/ directory because this file has a function that compares the user of the file.php with the user of file it tries to create in wp-content folder. If it is the same, WP can update the plugin normally through admin web interface otherwise it raises the FTP upload dialog.
chown -R www-data wordpress_installation/wp-admin/includes/file.php
See here https://stackoverflow.com/a/53166416/6881647 and here https://github.com/WordPress/WordPress/blob/56c162fbc9867f923862f64f1b4570d885f1ff03/wp-admin/includes/file.php#L1549 for the code itself.