Please refer to this blog post. Azure SQL Data Warehouse is now named Azure Synapse (Dedicated SQL Pools or Serverless SQL Pools). SQL Pools are dedicated Azure SQL Data Warehouses. Serverless pools are like dedicated pools but no need to provision pools, you just query and it will destroy resources once finished.
Synapse is the only solution that connects natively to other Azure services. Synapse integrates with Azure Purview (Data Governance), Power BI (Business Intelligence) to make data-driven business decisions, and Azure Machine Learning to use organizational data to train ML models and make business decisions.
Dedicated pools can scale to peta-bytes but Azure SQL can scale to 14 TB or 4 TB depending of the model and Hyperscale can scale to 100 TB.
Azure Synapse has a nice integration with Azure Data Factory for ETL and ELT processes, Azure SQL does not have that integration.
Azure Synapse dedicated/serverless pools can use relational table schemas as Azure SQL does, but you are supposed to use denormalized schemas to speed up queries on data warehouse.
Azure Synapse dedicated pools can be paused at any time, Azure SQL serverless can be paused after one hour or more of inactivity, the rest of Azure SQL options cannot be paused.