what do you mean by relative? that node is for adding rotation not setting rotation so its not really relative or world. if your talking about how if you try to add say 90 to the rotation but it ends up being much more then thats due to the scaling. you can change the scaling amount in the player controller as shown in the below picture.
another option would be if you wanted to set the relative rotation of the camera you could just get the relative rotation then use a combine rotator and a set relative rotation. though this may not give the effect you want if you directly target the camera.
you say you want your pawn to rotate on the relative axis but actors always rotate on their own axis so i dont really understand what you mean. in general better define and describe your question so we can have a better understanding of what your looking to do.
