@demo-user Serverless SQL Warehouses and the Express account type are designed for simplicity and rely almost exclusively on the cloud provider's secure identity mechanisms.

• Serverless SQL Warehouses (and Serverless Jobs) do not currently support configuring generic S3-compatible endpoint URLs and access keys
• Complex, non-standard cloud integrations are often limited or unsupported compared to the Enterprise account type

The only reliable and supported way to connect to a generic S3-compatible object store using a custom endpoint and access keys is by using Provisioned Compute where you control the Spark configuration.