"Escape to Salvation" - "Magnificent Retreat" [Campaign 4, Mission 4]

Hello, I apologize for the off-topic message. But did I understand correctly that, as of today, to complete this mission (if it's impossible with Kujin, playing on version 3.1), you need to either: 1) Reinstall the game with patch 3.0, which will allow you to stop it and Gotay before attacking the demon castle, or 2) Download pre-made save files and play through them to the end of the mission? Is that correct?