going to answer myself.
as of hive3, its not yet possible to directly bulk load external datasets (e.g. parquet / orc) files. so its necessary to do the following.
create temporary managed hive table
LOAD DATA INPATH the parquet / orc / csv into the temporary managed hive table
create external table as iceberg.
Select * and copy into the external iceberg table
this has worked with the following iceberg features.
write, append, time-travel