Both should work with WordOps.
Having re-read your initial post, it looks like you have to add /var/cache/nginx
to the two PHP pool files WordOps uses - by default the path is set to /var/run/nginx-cache
. The two files are located here:
/etc/php/7.4/fpm/pool.d/www.conf
and /etc/php/7.4/fpm/pool.d/www-two.conf
Add it to the end of this line like so:
php_admin_value[open_basedir] = "/var/www/:/usr/share/php/:/tmp/:/var/run/nginx-cache/:/dev/urandom:/dev/shm:/var/lib/php/sessions/:/var/cache/nginx/"
Restart PHP.