Random and brutal framerate drops on PC, CPU bottleneck?

I'm playing on an 5800X and RTX 3080. Still in the opening area, in Medical, and there are some areas where my framerate tanks from 120 to 80 for no visible reason. I'll be going down a hallway, specifically the first plant-filled hallway, and it'll happen there. Then I reached a room with a briefcase holding a keycard, and in that same room, I can look one direction and maintain my locked 120, but then look 90 degrees to the left, and have my framerate drop to the 70s. My GPU usage also drops, indicating a CPU bottleneck.

Screenshots here: https://imgsli.com/MzQwOTk2

This is really bizarre. I know UE4 has some bad CPU bottlenecks, but I've never had this drastic of a swing in the same area, or standing in the same place. Anybody else have similar experiences?