I think that the presumption is being made that creation is over, but this need not be so.
If we are not a finished product , but part of an ongoing project , then processes of refinement , tempering , winnowing, and shaping are easy to explain.
I don't think that the full purpose of Satan is really known to us, but from reading in the book of Job, I have the opinion that his role is that of prosecutor and accuser.
There seems to be also a presumption that the purpose of man is to be happy, I don't see the scripture or the logic in this .