Thanks for playing and congratulations on beating the game!
There isn't a way to unlock all of the Bad Ends in the journal, but the fans have put together a list of Bad Ends and other information in this Google Document: https://docs.google.com/spreadsheets/d/16wZ7XEtz3pdHbk7_Z7UxtN-o1XI8QUUpIaUpPKCFv_0/edit?usp=sharing
Follow the instructions there and you should be able to find all of them!