I completely don't understand your point. I have created EXTERNAL TABLES in hive_metastore catalog as :

CREATE TABLE hive_metastore.dd_omp.versioncompatibility LOCATION 'dbfs:/mnt/{storage_account}/{blob_name}/{path_to_data}';

(I am using mounted path here)

I don't have a problem to select the data until I set hive version in advanced option of cluster.

I don't want to make it MANAGED TABLE, I need to still have EXTERNAL TABLE, but in Unity Catalog.