@Mr_NutterButter
At low settings the GPU doesn’t have much to do, so the CPU can go full throttle, while on max settings the GPU is spending so much time working on graffic the CPU is waiting for it to catch up and has lower usage.
It is generally true of most games though, but UE probably comes with an added side of DLSS TAA motion blur post process garbage at every setting. But it’s why for gaming benchmarks, in CPU benchmarks people run at low resolutions and settings but for GPU they run at max settings 4k.