While gaming engines can have value for autonomous vehicle design and testing, they also have severe limitations. These are due to not having a deterministic architecture or use of federated modeling. This severely limits their ability to run complex math, especially hundreds of physics models at one time. Because of this there is no gaming based simulation company I am aware of who even attempts to model every real world object, sensor, location etc visually let alone in physics. Because of this AV systems will wind up with Planning and Execution issues when complex scenarios are involved.
DoD simulation technology resolves all of this. And can integrate with Unreal as the core architecture leaving Unreal to handle visual rendering which it does well.
(I would be glad to provide a demo of this capability)
Proposal for Successfully Creating an Autonomous Ground or Air Vehicle
Simulation can create a Complete Digital Twin of the Real World if DoD/Aerospace Technology is used