Do you mean that each time you press D, the character always turns right 90 degrees, and each time you press A, character always turns left 90 degrees?
and then if you press W, character goes forward whichever way it is currently facing?
if that is the case you don’t want to set an absolute rotation. instead, you want to get the current world rotation and then add 90 or -90 to the yaw, and then use the result of that to set new world rotation.
dont have unreal open now, will show some blueprint code later if you still need it.