Sorry, I didn’t see your reply to this. I was only able to narrow it down and get the project stable by working out which materials were causing the hard crashes.
It actually took many hours to identify and resolve the offending materials. One of them was a 2D interface material with some transparency if I recall.
I’m not sure exactly what conditions are causing the crashes, but it’s definitely all related to materials, so just go folder by folder, and if clicking a material crashes the engine, then open the engine under Vulkan and remove the transparency pin. See if it then works.
Edit: Obviously start up with a blank map or it will crash straight away.