Why does frame rate drop to 75 FPS in multiplayer combat?

Frame rate dropped to 75 FPS with 0.5s audio lag in multiplayer. CPU usage hit 85% due to a Logitech G HUB conflict. I used GamePP Peripheral Driver Conflict Detector to set the service to Manual. Frame generation stabilized at 7-10ms via OBS, and frame rate recovered to 115-120 FPS.