I think editing the parameters of CameraShake in run-time is not possible (in blueprint). It also seems to me that this is intentional.
CameraShake supports both oscillation and animation. You can switch between different CammeraShake parameter sets on the fly. You can scale and rotate it run-time.
If you need something super, super custom from your camera movement it might not be considered “shake” anymore. There is another class called CameraModifier which runs after the CameraManager class with a dedicated ModifyCamera() function.
Quite frankly, I cant think of a scenario where my shake can’t do all I need just by scaling and rotating it. Can I ask what the end goal here might be?