To access audience data from Google Analytics 4 in BigQuery, you must first ensure your Google Analytics 4 property is linked to BigQuery. The data will then be exported on an ongoing basis from Google Analytics to your BigQuery dataset. Audience data, however, may not directly be available in BigQuery. Instead, you would use the user_properties object field, which contains user-level properties set by an analytics event. But keep in mind, this requires proper audience definitions in GA4 via event parameters or user properties(data collected might differ). After structuring the data in BigQuery, you can connect your BigQuery project with Looker. In Looker, you’d need to build a LookML model & view using the field data of your BigQuery project. Then, you can apply it as a filter to create the dashboard or report you need in Looker Studio. Please remember that complex queries in BigQuery can cost you as it follows a pricing model.