ORA-39014 import in Oracle 19c from DMP file of Oracle12c
It looks like your Oracle instance is failing you. But let's roll it up from the beginning.
IMPDP in Parallel
To execute the IMPDP command with the PARALLEL parameter you have to meet the following requirements:


This parameter is valid only in the Enterprise Edition (check) of Oracle Database 11g or later.

To import a table or table partition in parallel (using PQ slaves), you must have the DATAPUMP_IMP_FULL_DATABASE (check) role.

Transportable tablespace metadata cannot be imported in parallel.

Metadata cannot be imported in parallel when the NETWORK_LINK parameter is also used

The following ojbects cannot be imported in parallel:

TRIGGER
VIEW
OBJECT_GRANT
SEQUENCE
CONSTRAINT
REF_CONSTRAINT.




Reference: 3. Data Pump Import | PARALLEL (Oracle Help Center)
ORA-xxxxx Errors

Disclaimer
Due to copyright restrictions I am only able to provide you with some general links to the Oracle Doc IDs which may or may not provide you with a solution to your issue(s). Registration is required to view this information in full.

ORA-00800 Errors

ORA-00800: soft external error, arguments: [Set Priority Failed], [VKTM], for Oracle Linux (Doc ID 2718971.1) (Oracle on *nix systems)
ORA-00800: Soft External Error, Arguments: [Set Priority Failed], [VKTM] [Check traces and OS configuration] (Doc ID 2551359.1) (Oracle on IBM AIX systems)

ORA-00313 Errors

ORA-00313 at Startup After a New Redo Log Member is Added (Doc ID 1005110.6)

ORA-07445

ORA-7445 Troubleshooting Tool (Oracle Online Troubleshooting Tool)

This option requires you to upload an IPS package to Oracle in order for them to analyse the data. If you create an SR with Oracle and supply the error message ORA-7445 in the case, then you will be automatically redirected to this tool. There is however a downloadable version under that link.
If All Else Fails
There do seem to be issues when trying to import 12c objects into 19c so you might want to contact a certified Oracle consultant or if you have a Support Identifier with Oracle open up a new Service Request.