I'm having the same bug, went to fight Gortash and the dragon but can't go back to the lower city without the game crashing at 33%.

By reloading saves I figured out that my problem is in the house of hope of all places ... but I can't find any dead body with >0hp.

I wonder if it's got something with the petrified bodies in there, in my run I tried a greater restauration on one of them and it just vanished.
My other theory is that it got something to do with the flaming ball that chases you after you free Hope, when I entered the boss fight with Raphael it disappeared and never came back.

Do you guys have any theories on what might work here? That fight was over 20 hours ago and I don't want to play all that over again.