Weird Glitching With Camera

I am making a game and all of a sudden my camera started doing what's happening in the video attached. I have no idea how to fix it and I made no changes to the camera that I know of that could have caused this. I created my project with the first person template in unity 2021.3.0f1. The only change I made that could have affected it was switching the input manager from just the new system to "both" so that I could use the old input system as well as the new one. The two things I have tested: 1) it's not my sensitivity, it works fine, and dragging around the editor is super smooth 2) it's not the frames because I tested this and it was a consistent framerate. Let me know if you have any ideas! I am really stuck with this and I don't know what to do. Video of it happening

 private void LateUpdate()
     {
         CameraRotation();
     }

     private void GroundedCheck()
     {
         // set sphere position, with offset
         Vector3 spherePosition = new Vector3(transform.position.x, transform.position.y - GroundedOffset, transform.position.z);
         Grounded = Physics.CheckSphere(spherePosition, GroundedRadius, GroundLayers, QueryTriggerInteraction.Ignore);
     }

     private void CameraRotation()
     {
         // if there is an input
         if (_input.look.sqrMagnitude >= _threshold)
         {
             //Don't multiply mouse input by Time.deltaTime
             float deltaTimeMultiplier = IsCurrentDeviceMouse ? 1.0f : Time.deltaTime;
             
             _cinemachineTargetPitch += _input.look.y * RotationSpeed * deltaTimeMultiplier;
             _rotationVelocity = _input.look.x * RotationSpeed * deltaTimeMultiplier;

             // clamp our pitch rotation
             _cinemachineTargetPitch = ClampAngle(_cinemachineTargetPitch, BottomClamp, TopClamp);

             // Update Cinemachine camera target pitch
             CinemachineCameraTarget.transform.localRotation = Quaternion.Euler(_cinemachineTargetPitch, 0.0f, 0.0f);

             // rotate the player left and right
             transform.Rotate(Vector3.up * _rotationVelocity);
         }
     }