File README.SUSE of Package nextcloud

To speed up nextcloud you should enable PHP OPcache

The OPcache improves the performance of PHP applications by caching precompiled bytecode. We recommend at least following settings:

Put this in this insert in /etc/php8/apache2/php.ini

opcache.enable=On
opcache.enable_cli=1
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=10000
opcache.memory_consumption=128
opcache.save_comments=1
opcache.revalidate_freq=1

Also you should set the memory_limit to somthing like >=512MB in
/etc/php8/apache2/php.ini and /etc/php8/cli/php.ini