The error is not primarily a Unity Catalog or permissions issue. It means the workspace does not have the Serverless Generic Compute Materialized View/Streaming Table preview enabled.

There are two important distinctions here:

If you are building a Lakeflow/Spark Declarative Pipeline,  The CREATE OR REFRESH STREAMING TABLE statement belongs in a pipeline source file and should be executed with Run file or Run pipeline in the Lakeflow Pipelines Editor and not run as a normal notebook query. Pipeline source files are evaluated by the pipeline engine.

Now if you are are creating a standalone streaming table from a notebook, Serverless Generic Compute support is currently beta, region-limited, and requires the workspace preview. A SQL warehouse is the simpler workaround; standalone tables can be created or refreshed from a Unity Catalog-enabled Pro or Serverless SQL warehouse.