When Moodle runs the PHP statement ini_get('file_uploads') PHP is returning 0 (or off).
If this is a server you manage and you have changed file_uploads in php.ini then you may need to restart the web server service to apply this change. This service may be httpd, php-fpm or apache2. On CentOS 8 the command would be systemctl restart php-fpm. If you need help with this, tell us details of your server's operating system (the name of the OS and version).
If this is a managed server, then you probably need to contact the hosting provider for assistance.
It's possible that the block_manager error is being triggered by the file_uploads problem so I'd get the first error fixed before looking at the second one.