I don’t think that sin being an inevitable consequence of free will would mean that God intended evil. If God decided to give humans free will knowing that they couldn’t help but eventually sin as a result of that free will it doesn’t mean he intended them to sin, just that he saw greater value in the granting humanity a free will and granting them an eventual redemption than he did in in having man eternally in the original state of justice. I do understand what you are saying though and have heard it before which is why I was asking if there was any official teaching on the matter.