Problem with Spline transform while aiming in First Person

Problem with transforming the spine bones while aiming in first person view. In the video , you can see that when the player is not aiming , it can see its body as intended , but when it aims , it rotates its spine bone unrealistically , so the character’s torso shifts closer to its lower body when I am looking down and it looks really awkword. I want to have a system where the character’s relative torso position moves realistically while aiming. This is my current setup.