I spent a lot of time, but finally I managed to kill the wither and create a lighthouse, when I placed it in my iron pyramid the lighthouse was activated, I assigned an effect and waited, but the achievement never came, I removed and placed the lighthouse and put different effects but nothing, you can not get the achievement my world is in survival and if you can get other achievements, it is curious that the most difficult achievement (or at least the one with the highest reward in points) can not be achieved.
:/