Found in another post ( [ContentMigration] foreman-maintain content prepare failed - #5 by touchardv ).
Ran command
sudo su - postgres -c "psql -d pulpcore -c 'UPDATE auth_user SET is_superuser = true WHERE id =1;'"
and retried, that seems to have worked, so that seems to be the permission error at least.
Tagging @Justin_Sherrill to make sure he sees the solution, if others have the same issue. 