utlrp.sql running extremely slow during db upgrade from 12.2.0.1 to 19.12

Hello:

We were upgrading a prod database from 12.2.0.1 to 19.12. Right after the upgrade step (./dbupgrade), we ran the required upgrade step to re-compile invalid with the following:

$ $ORACLE_HOME/perl/bin/perl catcon.pl -n 1 -e -b utlrp -d '''.''' utlrp.sql

or

SQL> @$ORACLE_HOME/rdbms/admin/utlrp.sql

We used the first command above at command line. But the job took 3 days for this db of 8 Tb with about 3100 invalid objects - it is still running now. So the db components are still in 19c "UPGRADED" mode - not in new db version 19.12.

So we are seeking advice from you on how to speed up and improve utlrp.sql performance in general and particularly during 19c upgrade.