Terrain not loading/No menu

I'm having an issue where I get to a certain point and most of the terrain isn't loading in and there's no access to the in-game menu.

Playing on Window's 10/Steam:

I'm at the beginning of the game when rook destroys the scaffolding at the ritual site and the game black-screens forever with audio intact (part of the problem but not the main problem). If I exit out of the game completely and load back in, it starts in the cut-scene of rook and companion shoving the pillar and it falling and so on and so forth. The game plays through the rest of the cutscene until rook blacks out after touching their head and seeing blood. 

Then, the game loads into a playable part with rook and the companion by the eluvian but most of the terrain isn't loaded in and hitting the button to get to the in-game menu appears to pause the game but there's no menu UI (so I can't load a save or go back to the main menu or anything). There's nothing I can interact with or any apparent way to move the story forward. (Also I can't die from fall damage in this state, I found out when I ran off the edge of everything.)

I've tried backing out and reloading the save, loading from an earlier auto-save, and from manual saves, and I've tried the whole game over with a premade character. I've tried uninstalling and redownloading the game and the game's already saved to SSD.  I've had Steam verify the game files several times. I'm already playing at the lowest graphics settings. All my drivers are updated. Someone help, I'm out of ideas of how to get through this. 

Picture attached of the partially-loaded game: