Hello, meanwhile, I've found a workaround to get the owner, or more likely the creator of the dashboard.

SELECT 
            request_params.dashboard_id AS dashboard_id,
            FIRST(user_identity.email) AS owner_email
        FROM system.access.audit 
        WHERE workspace_id = '{workspace_id}'
            AND service_name = 'dashboards' 
            AND action_name = 'createDashboard' 
            AND response.status_code = 200
        GROUP BY request_params.dashboard_id