Well the error is talking about the hive metastore so that means youre still not connecting to your external location.

Can you create a table on the external location with this (assuming you have a json file in a blob folder location)?

# Set Variables
catalog_name = test_catalog
schema_name = test_schema
catalog_container = <catalog container string>
storage_account = <storage account string>
blob_path = f"abfss://{catalog_container}@{storage_account}.dfs.core.windows.net/<folder path>"
 
# Create Catalog if it doesn't exist
spark.sql(f"CREATE CATALOG IF NOT EXISTS {catalog_name} MANAGED LOCATION 'abfss://{catalog_container}@{storage_account}.dfs.core.windows.net/'")
 
# Create Schema if it doesn't exist
spark.sql(f"CREATE SCHEMA IF NOT EXISTS {catalog_name }.{schema_name }")
 
# Read Files into Dataframe
df = spark.read.format('json').load(blob_path)
df.display()