I think this is one instance there the developers need to add their knowledge. Could someone who knows how to ping them, please assist me in this.
When a thread hit a bit of code that needs to have data given by another thread there will be a delay. To avoid this the processors have a prediction algorithm to keep the scheduling at optimum. But most effort on the AMD side is going towards optimize for the single processor scheduling. At least when it comes to Ryzen and Threadripper models. The EPYC processors are a different matter as the multiprocessor setup is more common. This is the hardware part of the answer.
But the Unreal Engine 5 (EA) might have some extra intelligence built in the code of the engine and thus sneak past the scheduling dilemma. For example (I am a noob on this) the Lumen part of the code could work more independent from the Nanite part and therefore UE5 developers have added some code to detect if there is a multiprocessor setup, and thus make some excellent use of this possibility.
On a side note, wonder if the Unreal Engine 5 will work well on the EPYC?