Another developer on my team managed to figure out the cause of the crash being related to the DX12 still having SM6 enabled as a targeted shader format, and hence content in engine was built using SM6 format which Vulkan doesn’t support, so having disabled SM6 and rebuilt the content with SM5, then switching to Vulkan after rebuilding resolves the issue. Though it then became apparent that Vulkan + SM5 doesn’t yet support Nanite and the likes, so Vulkan really needs to catch up on that front…