Those dimensions aren’t exposed by the standard YouTube Analytics API connector in Looker Studio. Audience demographics such as gender and age are only available if your channel meets YouTube’s data thresholds and you access them via the YouTube Analytics API directly, using the audienceGender and audienceAgeGroup dimensions. Artist-related fields are not part of the public API unless you are using YouTube Analytics for Content Owners (via Content ID CMS) and have the necessary CMS account permissions. If you need these in Looker Studio, you’d need to pull them with a custom API query to BigQuery or Sheets first, then connect that dataset to Looker Studio.