Nextcloud as a SimpleSAML IDP auth backend?

Has anyone succeeded in setting up a SimpleSAMLphp installation with Nextcloud as the IDP auth backend?
i.e. have simpleSAMLphp authenticate external service providers against the Nextcloud DB users utilizing the sql_auth backend?

I am trying to use Nextcloud as the central system for various webservices and simpleSAMLphp would work well for that as an identity provider, but contrary to systems like Drupal, Wordpress, Django etc. I can’t find much details on how the Nextcloud database is structured and how the passwords are stored (hash+salt?) etc.