Is there a way to see all the available variables inside content?
Normally it works that way but Views templates may be different.

Enable Twig debugging.
Add Devel and Kint: composer require drupal/devel kint-php/kint
Enable Devel: drush -y en devel
Inside the template put {{ kint(content) }}, flush caches, visit the page and you should see what else can be found inside content.