Calculating Angle Vectors that are rotating

So I’m having trouble calculating the angle between vectors that are changing rotation.
Basically I have a pawn character that I hold-click on in VR with my motion controller and that shows me a Widget pop-up above his head with three icons. I want to calculate the angle of the motion controller’s hand with the Widget Pop-Up and give me the angle the motion controller is at. With that I want to split the 180 angle into three and have each area make you choose that area’s pop-up icon. In the image bellow I drew each area with a different color.

I tried to use Find Look at Rotation and it worked a little but doesn’t take rotation into consideration as I’m always having the Widget rotate towards the player to face him.

I’m not sure how to calculate this to make it work from all directions and rotations.
Thanks in advance for the help. :slight_smile: