I think you are asking two different questions here. One is, does what we know about QM mean that determinism is false? The answer to that seems to be: it depends to some extent on your interpretation of QM. However, on any interpretation it is the case that there are fundamental limits to our ability as observers to predict outcomes. Even with the maximum theoretically available information we can't do better than calculate probabilities of various outcomes.
The other question is, does the fact that we are uncertain about something mean that it is not determinately true one way or the other? As your apple example shows, the answer is no. The fact that you don't know whether your aunt's pies are made with hand-picked apples doesn't mean there is no fact of the matter. For a start, your aunt probably knows. Here the uncertainty is not some fundamental theoretical uncertainty that arises from QM, but the common or garden variety of uncertainty that we suffer from all the time because we are finite beings with limited information and limited ability to process it.