Force spring arm component to ignore parent's rotation?

I am creating my first project with UE4 and I would like to have a movable player character that has a shield that the user can rotate around their character independently of where the character is facing. I currently have this solution which is working ok:

and the shield will rotate around the player when the user presses LMB.

However, the shield will also rotate when the user moves the character with the normal WASD keys. I would like to make the shield only rotate when the user presses the LMB, I do not want to rotate when the parent (player) rotates.

My thought is that I need to change the input of the delta rotation from the static amount to be relative to where the player is currently looking, but I’m not really sure where to begin there…

thanks for any advice!