Hello @Joshua Adeleke!
I'm not used to HAR files + Hive, but did you set the following parameters?
hive> set hive.archive.enabled=true;
hive> set hive.archive.har.parentdir.settable=true;
hive> set har.partfile.size=1099511627776;
hive> msck repair table <EXTERNAL TABLE>;
Hope this helps!