Hi,
You can simply use “GetInputMouseDelta” or “GetMousePosition” nodes instead of input nodes. First one will give you the delta position of your mouse cursor per frame and the later will give you the position of your cursor based on your viewport coordinate. Both are fixed to the viewport orientation so they are independent of your character world rotation. You probably will need to use a multiplier to adjust the movement rate. At the end you need to set your character mesh component local rotation. Read mouse x/deltax values to set yaw and mouse y/deltay values to set pitch. if you use the first node then you’d better to use “AddLocalRotation” node instead.
Update:
Make sure to uncheck “Use Pawn Control Rotation” checkbox inside FP camera details panel.
Hope it helps,
Regards,