Non existence is nothing to be scared of as we simply won't exist, we won't even be aware that we are dead. One would need a consciousness to be able to feel anything. I believe it to be just like how time passed before we were born and yet we were not aware of anything.
Death is inevitable for us all anyway, as humans we only exist just to die and be forgotten about so there is no point to fearing it as we will all be gone someday no matter what. I view permanent nothingness as being the best thing possible as it's freedom from this nightmarish existence. If we are dead then there is nothing to worry about. Everything that causes us to suffer will be gone.