DWU used, defined as DWU limit * DWU percentage, represents only a high-level representation of usage across the SQL pool and is not meant to be a comprehensive indicator of utilization. To determine whether to scale up or down, consider all factors which can be impacted by DWU such as concurrency, memory, tempdb, and adaptive cache capacity. We recommend running your workload at different DWU settings to determine what works best to meet your business objectives.
Reference:
https://docs.microsoft.com/bs-latn-ba/azure/synapse-analytics/sql-data-warehouse/sql-data-warehouse-concept-resource-utilization-query-activity